Outlook Error: The file *.ost is already in use by the maximum number of applications
When trying to view a stripped message, there is an Outlook Error: The file *.ost is already in use by the maximum number of applications. Close some of these applications and then try again.
There can be several fixes for this Workaround 1 Close Outlook Open Task Manager and check to see any other open processes that will be using the OST. Kill these processes.
Workaround 2 1. Close Outlook. 2. On the Start menu, click Run. 3. In the Open box, type
C:\Program Files\Microsoft Office\Office12\scanost.exe (You may need to change that location if you are using an older version of Outlook) 4. Click OK. 5. Click Scan all folders, this may take several minutes. 6. Select the Repair errors check box. 7. Click Begin Scan.