How to fix problems after reconnecting Microsoft Outlook client to

March 6, 2020 |

greater than 18 minutes

Sometime in 2016/2017, Microsoft rolled out a special upgrade where email accounts created on its platforms or sites got moved to The migration was mandatory. Users had no say in the matter. They even had to reconnect their Outlook 2013 or Outlook 2016 clients to – if they wanted the desktop email applications to continue to function like before.

Should I migrate to

You do not get to decide anything here. If you are reading this, then Microsoft probably moved your email account over to To be fair, a few years have gone by since Microsoft worked on the migration processes. What you should worry about instead is migrating your email client to – if you are yet to do so.

What is important when migrating to Things to keep in mind

If you are yet to move your email client to and perform the reconnection tasks to configure your email client for uninterrupted access, then you might want to take note of certain things. We gathered the most important details and facts.

  1. Usage of multiple devices: If you use multiple devices, then all your machines using the Outlook application for Windows will have to be reconnected to In other words, you have to perform the same reconnection tasks on all your computers. The email access you acquire on one PC will not be carried over to another device just like that.
  1. Usage of mobile phones: Your mobile phone (regardless of how advanced or powerful it is) cannot use the same Outlook email client found on PCs. Even the smartphones running the Windows mobile OS provided by Microsoft have to get a different email client. Well, here’s the good thing: the email clients on mobile devices do not have to reconnect to for any reason.
  1. Usage of Macs: Macs do not run the same Outlook applications found on Windows devices. The reconnection and set-up procedure is directed at users with Outlook clients for Windows. Therefore, if you use Outlook on a Mac, you do not have to do anything associated with the reconnection procedure.
  1. Data transfer: From the notes provided by Microsoft, we learned that the company intends to move all data hosted on the old servers to the ones for Nevertheless, the packages for drafts and outbox will be left behind – since they are stored on the devices involved locally. If you do not want to lose the stuff contained in those folders or directories, then you have to back them up and then later restore things from the backup.

In a previous guide, we covered the processes that make up the reconnection operation to (for upgraded email accounts). If you refuse or fail to reconnect your email and the email client as you are supposed to, then you will experience several problems – for example, emails will stop syncing to the Outlook application on your PC.

In this guide, we intend to show you how to fix issues with migration. Yes, certain problems spring up after you reconnect your Microsoft Outlook client or email to Sure, the upgrade comes with certain improvements, but the migration processes are far from flawless.

How to troubleshoot problems that occur after migration

We intend to examine the most popular issues of the lot and proffer effective solutions to them.

  1. An issue where the email account name shows up as outlook_[long string of characters]

A good number of users – who performed the migration tasks – have complained of a serious issue where the names of their email accounts appear as outlook_ [long string of characters] in the Folder Pane. This discrepancy constitutes a problem because recipients receive messages where outlook_ [long string of characters] gets displayed as the sender’s email ID.

If the sender in such scenarios tries to respond to the email ID provided, the mail bounces back or the sending operation fails – because the address is wrong or invalid. The problem in view seems to manifest itself only on the Outlook desktop application, and not on the site or platform accessed on any web browser.

Solution: You should be able to fix the problem by firing up your web browser, going to the Manage account or profile menu for your Outlook account, and then setting your Outlook email ID as your primary alias. Ideally, you should get rid of all other email IDs. After you make the necessary alterations, you have to restart your computer.

Outlook will reconnect to Microsoft servers and take note of the new changes, which means the problem will no longer manifest itself. If the described fix fails to work for you (even if you did everything correctly), then you might have to come to terms with using your Outlook email on your web browser to circumvent the problem for the time being. Microsoft will eventually release a fix for the bug (or patch to eliminate issues) in a new Outlook build or release.

  1. An issue where repeated credential prompts appear on Outlook for accounts:

The issue where repeated credential prompts keep bothering users has been known for quite some while now; it precedes the migration or upgrade events for Outlook. The problem manifests itself on almost all Outlook versions regardless of their build or release date. If the repeated credential prompts bother you after you reconnect your email or email application to, then you have to test things to check if the problem has anything to do with the two-step verification function.

Some users managed to resolve the problem by doing away with the two-step verification property, which is meant to protect their accounts from unauthorized access, so you too might want to do the same thing. If the problems persist even after you put down the two-step verification function, or if you cannot bring yourself to do away with the property for security reasons, then you have to try to get help from the SARA Tool designed to troubleshoot Outlook and Office 365 problems in Windows.

You can also try deleting Windows credentials, rebuilding the profile affected by the issue, and so on. Some users had some success with such unorthodox procedures. Those operations are more or less harmless, so you will not lose much by trying them. If they fail, then you can try creating an App Password to add the affected account in Outlook. If the problem continues to bother you, then you might have to fill out a form to contact Microsoft to tell them of the issue.

  1. An issue where Outlook frequently crashes after migration to

There is no effective or sure fix for the problem here. We do not even know what triggers the crashes. Microsoft has directed the affected users – whose Outlook desktop clients become unstable after the migration – to create a new Outlook profile and use it for the relevant purposes.

If Microsoft’s recommendation fails to do enough to resolve the issue in your case, you can try to use the SARA tool to troubleshoot things and see what comes off.

  1. A problem where users are unable to send emails from third-party email IDs when an profile serves as the primary account:

There seems to be a bug that prevents users from sending emails using their accounts from other email service providers (for example, Gmail from Google, Yahoo mail from Yahoo, and so on) when an profile is being used as the primary account. After some research, we figured out the issue has nothing to do with a bug present in the Outlook code. The inability of third-party email accounts to perform sending tasks is rather a feature of design.

Yes, Microsoft programmed the Outlook application to resist user attempts to send emails using the accounts from other email providers, however weird that might appear to you. Well, it seems Microsoft is trying to get users to use its products (email accounts hosted on its platform). Unsurprisingly, the Outlook email client will allow you to send messages using emails with these suffixes: @Live, @Hotmail, @Outlook, and others from Microsoft.

Well, if you must use the Outlook client or desktop application on your computer, then you might have to come to terms with Microsoft restrictions that affect the capabilities of the email accounts provided by other service providers. At least, you now know the cause of the problem (if it is actually a problem in the first place). If you do not agree with Microsoft policies, then you might have to switch to a different email client.

  1. An issue where recipients get a winmail.dat file attachment (that comes with emails they receive from users):

If the recipients of the messages you send on Outlook using your email account are complaining that your emails come with a winmail.dat attachment, then you have to tell them that bugs or inconsistencies in your Outlook email client are responsible for the problem. We do not know why the Outlook application does some of the things it does. The issue in view is still under investigation. Well, a decent solution is yet to be found. Otherwise, we would have spelled out the instructions here.

As far as we know, the winmail.dat attachment issue does not manifest itself when the email is sent from the Outlook account accessed on a web browser. If the unnecessary file in your messages is causing you any trouble – in that your recipients are starting to worry before opening your messages – then you might want to keep your emails off the Outlook application for the time being.

Ideally, you should perform all the relevant tasks – especially sending messages – on the Outlook platform on your web browser. You can rest a bit knowing that whatever inconvenience you are suffering now is not going to last forever.

  1. An issue where the company name disappears in contacts during syncing to the server and related operations:

Unfortunately, we do not know of any proven solution to the problem here either. Certain workarounds might do enough to resolve the issue in your case, though. For one, you can try to add the details of the crucial contacts on (the site itself). This way, you get to circumvent the processes that give rise to the problem or avoid the events in which it plays out.

Alternatively, you can reinitiate the syncing operations for Outlook again. You might end up having to trigger the sync process several times before things finally work out well.

  1. An issue where the sender’s email gets included in the ‘To’ field erroneously while the email is being sent:

Some users reported an issue they encounter each time they try to add multiple recipients to an email. Outlook automatically adds the sender’s email to the field for ‘To’. This operation is executed in error, but the cause is unknown. At best, we can provide a workaround or a procedure you can use to bypass the effects of the issue.

If the same events play out on your computer – if you are experiencing the same problem – then you have to delete the surplus email manually each time you try to send a message to many addresses at once. Hopefully, the bug that causes the issue gets resolved in a future update.

  1. An issue where users are unable to send emails to a contact group in Outlook:

If you are one of those users who see the “An unexpected error has occurred” message in the Outlook application when trying to send an email to a contact group, then you have to resolve the problem through an unorthodox procedure. Yes, no proven fix has been found to the issue here.

The workaround requires you to expand the contact list and then force Outlook to send the email to the list of IDs. Yes, the path described is not as efficient as it should be – given what purpose contact groups are supposed to serve in the first place – but it works. You can only hope that the issue has come to Microsoft’s attention. Otherwise, it might not get resolved even in a future or new build of the Outlook client for desktop computers.

  1. An issue where the email always appears in the From field:

Some users – especially those who have multiple accounts set up or associated with Outlook 2013 or other Outlook clients for Windows – struggle with an issue where Outlook applications default to the email ID in the From field whenever they try to send emails using the other accounts they have. Unfortunately, we do not know of any procedure that can be used to alter the course of events in the situation described.

You must make do with a workaround. In this case, you can choose one from several workarounds. If the issue does not bother you too frequently – especially if you use your personal account rarely – then you can always alter the contents of the ‘From’ field each time before you click on the Send button. Yes, you can afford to do this every time – if you do not send that many emails.

However, if you need a workaround that will serve you for all time, you can try to create an empty Outlook Data file and then restart the Outlook application on your PC.

How to resolve Outlook connectivity problems after migration

Some users reported that they could not get the Outlook application to connect to the relevant servers after the migration. If you too are experiencing the same issue, then we recommend you restart the Outlook application. If things do not improve, then you must also reboot your computer to see what comes of this procedure too.

Most connectivity issues with applications tend to disappear after users restart the affected programs or their computers. If you are still struggling with Outlook connectivity issues – even after you went with our recommendations – then you have to try to troubleshoot the issue.

Ideally, you should begin with the first procedure on the list and (if necessary) work your way through the rest in the order they appear.

  1. Check for and turn off the Offline function:

If you cannot get the Outlook application to connect to the internet as it is supposed to, then there is a good chance the program is currently in Offline mode, which means it is configured to avoid or evade web access. You need not bother yourself with the ‘why’ or ‘how’ your email client got into a mode that restricts internet connectivity.

What you should do is work towards getting it out of Offline mode. These are the instructions you must follow:

  • Open the Outlook application by clicking on the application launcher or shortcut on your desktop.
  • Assuming the Outlook window has come up on your screen, you have to click on the Send/Receive tab.
  • Now, you have to find the Work Offline button and click on it. Do whatever you have to do to disable the Offline function.

Since the application is no longer in Offline mode, you should see a message stating that it is trying to connect. If Outlook connects to the relevant servers successfully, then you will know your connectivity travails are over. Otherwise, you have to try a different fix.

  1. Rebuild the Outlook data file:

Outlook, like most applications, uses certain packages – which it creates, manages, and alters – for different purposes. Unfortunately, the relevant data are stored in file types that are vulnerable to errors, corruption, and related shortcomings or problems. Your connectivity struggles in Outlook might be down to the application being unable to access its data files – because they became damaged or got deleted.

Fortunately, you can always rebuild the data file through simple operations to make things right. Go through the steps below:

  • First, you have to close the Outlook application. You must also go a step further to confirm that no Outlook process or component is active.
  • Here, you have to fire up the Task Manager application through the Ctrl + Shift + Escape keyboard shortcut.
  • After the Task Manager window gets brought up, you have to go through the entries under the Processes tab and other locations.
  • If you see anything related to Outlook, you have to do a right-click on it to access its context menu and then choose the End task option.

You have to perform that termination task to ensure everything related to Outlook is put down. Since you are now sure of things, you can proceed to the major phase of the work here. Continue with the instructions below:

  • Click on the Windows button on your desktop screen to see the options and programs that make up the Windows Start menu screen (or give the Windows logo button on your machine’s keyboard a tap for the same outcome).
  • Input Control Panel into the text field (that Windows brings up the moment you begin to type) to perform a search task where those keywords constitute the query.
  • After Control Panel (App) gets displayed as the main entry on the results list, you have to click on it to fire up the application in view.

Windows will bring up the Control Panel window now.

  • Go through the options on the main screen. Click on Mail (or this option’s icon).
  • On the screen or window that follows, you have to click on the Data Files button to proceed.
  • Now, you must go through the items listed to find the file with a name that corresponds to your email address.
  • Click on the file for your email address to get it highlighted and then click on Open File Location.
  • Check what extension or format the file is in now.
  • If the file is in the OST format (with the .ost suffix), then you have to rename it to .old. You can perform the rename task this way:

Click on the file to get it highlighted, right-click on it to see the list of options available for it, and then choose Rename. You will now have to add the .ost term to the end of the file name and save the changes you just made.

  • At this point, you have to close all the windows you opened earlier and then fire up the Outlook application.
  • After the Outlook window comes up, the program will start rebuilding your data file.

It might take some time (anywhere from 10 minutes to even up to an hour). The operation runtime here is somewhat dependent on the number of Outlook files you have and your machine’s capabilities.

  • Do not close the Outlook app while the program is still busy working on your data file.

Once Outlook is done with the data file rebuilding operation, the application will display a message stating that all folders are up to date.

  • After the relevant notification gets brought up, you must take it as confirmation of the data file rebuild success. You must then test things in Outlook to see if the application can now send and receive messages using your internet connection.

If the file you found earlier is in the PST format (with the .pst suffix), then you have to go through a different path. You must follow these instructions to run the Inbox Repair Tool to fix things:

  • Open the File Explorer application by clicking on its icon or shortcut on your taskbar or using the Windows logo button + letter E keyboard shortcut.
  • Once your system brings up the File Explorer window, you have to navigate through the directories on this path: C:\Program Files or C:\Program Files (x86)
  • You must fill the text box in your current location (in the top-right corner of the program window) with this term to perform a search task there: scanpst.exe
  • You have to click (or double-click) on the relevant entry on the results list displayed to run the application.

Windows will bring up the window for the repair utility now.

  • Check and confirm that the default .pst or .ost file in your case has been selected.

Otherwise, you have to do the appropriate thing by finding the required file and selecting it so that it appears on the repair utility window.

This guide might come in handy:

  • Path for Outlook 2019 users –

C:\Program Files (x86)\Microsoft Office\root\Office16

  • Path for Outlook 2016 users –

C:\Program Files (x86)\Microsoft Office\root\Office16

  • Path for Outlook 2013 users –

C:\Program Files (x86)\Microsoft Office\Office15

  • Path for Outlook 2010 users –

C:\Program Files (x86)\Microsoft Office\Office14

  • Click on the Start button (close to the bottom of the repair utility window).

The repair tool will now begin its work by running a few scans on the data file. If the utility finds an error, it will bring up a window or dialog where you have to click on the Repair button to continue.

  • We recommend you click on the box for Make Backup of Scanned File Before Repairing to get this parameter selected – if you ever see it while the repair utility executes the necessary operations.
  • In any case, after the repair processes reach completion – which means Outlook ends up with a normal data file – you have to open the Outlook application and confirm that everything regards your connectivity is now in order.
  1. Repair your Office installation:

Outlook is one of the Microsoft applications that get bundled in the Office package for computers, so if you want to repair Outlook, you have to repair Office. We are recommending the repair procedure as a fix to Outlook connectivity problems because it consists of processes known to bring changes that eliminate inconsistencies or discrepancies in the program code.

If the Outlook client on your computer is failing or refusing to connect to the internet because it is broken or out of order, then the repair operation is likely to deliver the results you need. These are the instructions you must follow to repair Office or Outlook effectively:

  • Click on the Windows button on your desktop screen to see the options and programs that make up the Windows Start menu screen (or give the Windows logo button on your machine’s keyboard a tap for the same outcome).
  • Input Control Panel into the text field (that Windows brings up the moment you begin to type) to perform a search task where those keywords constitute the query.
  • After Control Panel (App) gets displayed as the main entry on the results list, you have to click on it to fire up the application in view.

Windows will bring up the Control Panel window now.

  • Go through the options on the main screen. Click on Programs and Features.
  • Assuming you are now on the relevant screen, you have to go through the list of applications installed on your computer.
  • Locate Microsoft Office. Click on it to get it highlighted and then right-click on it to see the list of options available for it. Choose Change.
  • You might have to click on the Change or Repair or Yes button – if your system brings up a confirmation prompt for the repair procedure.
  • Assuming you are now on the relevant Office window or dialog, you have to follow the on-screen instructions and guidelines to get the utility to repair your installation for all Office applications.
  • Once the repair processes reach completion, you have to restart your computer to round up things.
  • After the reboot, you must then launch the Outlook client to see if the connection issues have been resolved for good.

Other things you can try to resolve Outlook connectivity issues

If you still cannot get Outlook to connect to the internet – which means the application cannot fetch your emails or send messages on your behalf – then you have to try the procedures and workarounds on the final list of solutions to the problem. One of the fixes here (in fewer details when compared to descriptions above) might succeed where the previous ones failed.

  1. Try to use the Outlook logging function to fix the connectivity issues – if you use an Exchange Server connection:

Outlook is equipped with a logging feature or functionality that you can use to figure out the cause of the connectivity issues. First, to access the feature, you have to turn on logging. After you enable logging, you will have to restart the Outlook application to get the app to replicate the events associated with its inability or failure to connect to the internet.

If you do everything correctly, then you are likely to end up with an error code or specific notification about the issue. Armed with the new information provided, you will be able to conduct further research on the internet to get a solution to the problem in view. This time, you are likely to find the answers you need.

  1. Recreate your profile:

If a solution to the connectivity issue suffered by Outlook continues to evade you, then you have to try to fix things by recreating your profile. You can create and then configure a new profile without having to delete the old one. You will need your account settings, so you might want to gather the necessary information before you begin.

You can access the account creation function from the Mail menu in the Control Panel application. Anyway, after you create a new profile, you have to use it to go through the Outlook account setup wizard. If the connectivity issues do not play out with the new account, then you will want to configure that profile as the default one in Outlook. You might then decide to delete the old profile – since it has become redundant.

  1. Restart your internet connection.
  1. Disable your VPN – if you use one. Uninstall the VPN program.
  1. Disable and then re-enable your internet connectivity adapter.
  1. Flush your DNS.
  1. Try to configure your DNS settings manually.
  1. Update Windows. Download and install all the updates that have been released for your computer or system configuration.
  1. Update Microsoft Office (and Outlook).


If you need your computer to perform tasks faster than it does currently, then you might want to fetch and run Auslogics BoostSpeed. With this application, you can execute top-level repairs and effective optimizations to improve the state of your PC – and those improvements are likely to translate into increases in the speed and performance of your device.

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