Getting error on multiple machines, .ost is in use and cannot be accessed. Close any application that is using this file and then try again.

Question

I have multiple users getting this error

After they Click Ok it is followed by this error

[![](https://learn-attachment.microsoft.com/api/attachments/ea480256-eab5-4f5c-bfc6-513122ff47c8?platform=QnA"https://learn-attachment.microsoft.com/api/attachments/8d4fae98-963f-4674-8dbb-603ee32c5d3b?platform=QnA" rel="ugc nofollow">\ Here is Everything I have done.

1. Rebuilt the email profile - Did not fix it, worked for a day or two and the error came back up
2. Uninstalled/Reinstalled office
3. Ran Updates
4. I even factory reset a machine and still getting the error message.
5. I have disabled all add ins
6. Starting outlook in safe mode does not fix the issue
7. Tried the outlook.exe /resetnavpane and this did not fix it either
8. Disabled and reenabled cached exchange mode I have noticed if a user closes outlook the process is still trying to run, I tested on a machine having the issue and it looks like closing outlook takes about 2-3 minutes to fully close, if you try to end the task in task manager it tells me you need admin privelages to close this program and I am system admin here and even made the users local admins, so basically Outlook is not closing correctly, sometime it works instantly but it is few and far between to get it to work correctly. if you close outlook and try to reopen the program after it closes, windows still sees outlook is open and most likely is throwing the above errors as it thinks outlook is still using the file. Another addition to add is if you have this error and try to go into Control Panel - Mail and look at email accounts, the following process is not responding \!\[\](https://learn-attachment.microsoft.com/api/attachments/73cd9f29-c779-489a-a6fd-fff2629adfa5?platform=QnA"https://learn-attachment.microsoft.com/api/attachments/8d4fae98-963f-4674-8dbb-603ee32c5d3b?platform=QnA" rel="ugc nofollow">https://learn-attachment.microsoft.com/api/attachments/8d4fae98-963f-4674-8dbb-603ee32c5d3b?platform=QnA"https://learn-attachment.microsoft.com/api/attachments/ea480256-eab5-4f5c-bfc6-513122ff47c8?platform=QnA" rel="ugc nofollow">https://learn-attachment.microsoft.com/api/attachments/ea480256-eab5-4f5c-bfc6-513122ff47c8?platform=QnA

Answer 1

Hi Steve Matera,

Good day.

Thank you for connecting with us in Microsoft community.

According to your description, seems like you have performed all the possible troubleshooting methods to resolve this situation, I would like to share some information with you, in order of your certain situation, as the Office 365 global admin may need to contact our Office 365 support team on the back-end side through an open service request so they can diagnose this specific issue through some more technical resources, If necessary, they may be collecting certain log information for further diagnosis. Since forum moderators have limited access permissions and resources, due to this reason we are unable to collect certain detailed information on the public forum for data privacy. 

For this standard process, here is the official document for the global administrator: Get support - Microsoft 365 admin | Microsoft Learn

Important note: If any organization's Office 365 Business/Enterprise / Education subscription is from a syndicated partner or reseller, and if the global administrator can't open the service request on their side, they may need to contact the reseller's support provider so they can help the global admin open the service request on their side. after the Office 365 support team can participate in the service request.

I would really appreciate your valuable time. Thank you for your kind cooperation.

Sincerely

Darpan