Outlook is using an old copy of your outlook data file

Question

For the last a couple of months, we've started getting this error from the users when they start Outlook.

"Outlook is using an old copy of your outlook data file"

As a workaround, we are creating the ost file again, but we need to find the issue and fix it.

Our systems are Windows 10 20H2 x64 + Office 2019 + FSL 2.9.7654 (January Hotfix) + ProfileType=3 + Outlook Cached Mode + nothing in the redirection.xml

According to the documentation of OfficeContainer, cached mode is not supported when differencing disk is used. I'm not sure if it applies to Profile Container as well.

Answer 1

Hello Sky,

Could you please try below steps, it works for others

Close Outlook. Type or paste this into the address bar of File Explorer then press Enter:

%localappdata%\microsoft\outlook

Delete the ost - name format will be emailaddress - you'll see the file extension only if you have the option enabled to show extensions (on View menu in file explorer)

The other way to find it is, with outlook open, right click on the top level of the data file - this is usually your email address - and choose Open file location. This opens file explorer with the data file selected. Close outlook and go back to file explorer and delete or rename the ost file.

Ref: https://answers.microsoft.com/en-us/msoffice/forum/all/outlook-is-using-an-old-copy-of-your-outlook-data/8522e1ec-2b7f-4d4a-964a-7af48aff15ca

--please don't forget to upvote and Accept as answer if the reply is helpful--

Thanks,

Mohammed S

Answer 2

Thank you for your answer Mohammed.

As I've said in my initial post; this is already what we are doing; creating the OST again.

Instead of doing this, we need to find the underlying issue and fix it.

Regards.

Answer 3

Try adding "Domain Computers" objects in the NTFS permissions of your profiles share and enable the "Access network as computer" GPO setting. This fixed the issue for us.