Offline folder (ost) is in use and could not be accessed.

[Allank]

I receive this error about every 10 minutes while connected using Outlook
2003 Pro. on Vista Business

The file C:\Users\katal\AppData\Local\\Microsoft\Outlook\outlook.ost is in
use and could not be accessed. Close any application that is using this file
and then try again.

I can't figure out what has it opened except Outlook.

 

[Roady [MVP]]

To name a few;
Fax-software
Sync Software
Anti-virus/spam software
Anything else that does some sort of integration with Outlook or relies on
Outlook data.

Did you always have this issue? What did you do before you got this issue?