Creating duplicate .OST files to the same user

Question

Hello, We are facing authentication issues ( password popup) frequently for O365 users ( 25% of users) in MS outlook since 2-3 weeks. Also identified multiple OST files are being created under the same path of same user, like josebego.ost, jobsebego.ost(1), jobsebego.ost(2), jobsebego.ost(48), each OST is in different sizes, the user profile path looks like this (%AppData%\Microsoft\outlook). We are having is latest version of MS Office, windows O.S is 10 & 11. Kindly advise how we can resolve the above mentioned issue.

Answer 1

Hi @Phanindra Kumar ,

If multiple OST files are being created under the same path of profile, it could be due to several reasons such as:

1. The Outlook profile is corrupted or damaged.
2. The OST file is not properly synchronized with the Exchange server, which is causing Outlook to create multiple files.
3. The mailbox size is too large, which is causing Outlook to create multiple OST files.

To resolve this issue, you can try the following steps:

1. Make sure the latest version of outlook.
2. Close Outlook and open the Task Manager, end all Outlook-related processes.
3. Delete all the OST files, and Outlook will recreate the offline Outlook Data File (.ost) the next time you open Outlook.

For the problem that outlook keeps prompting you to enter credentials, you can refer to this article: https://learn.microsoft.com/en-us/outlook/troubleshoot/authentication/continually-prompts-password-office-365 If the issue persists, you can try creating a new Outlook profile: go to Control Panel > Mail > Show Profiles > Add. Follow the prompts to create a new profile. Once the new profile is created, open Outlook and configure it with your email account.

If none of the above steps work, you can try repairing the Office application.

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