I find that Outlook data files are both robust and persnickety. They survive crashes and corruptions, but can be very particular!



I seem to have fewer problems since I began doing these maintenance steps:





1. Once in a while, review your messages and reduce their numbers. For example, delete the messages in the "Deleted Items" folder, and delete messages in the Inbox that have large attachments that you don't absolutely need to keep.


2. Once in a while, compress the data files. Deleting messages will not reduce their size. Only compression does that. In the main Outlook user interface, right click the account, choose "Data File Properties...", "Advanced", and then "Compress Now."



3. Regularly backup your data files. I use a backup system that copies my .pst files to the cloud at least once every day or two. A couple of times, I've restored day or two day old .pst files.


I avoid repairing .pst files unless there are no alternatives. Once or twice, I restored a .pst file from backup and ran scanpst.exe. Outlook is still working on my machine, so I guess I did something right... or almost right!