Issue
On the admin site you receive a Object reference not set to an instance of an object when you click on most links in a given repository.
Solution
Have a web-site administrator perform a recycle on the app pool that the Vault site is running in (the Vault support site recommended a full IIS reset but this will reset everything on the web server). In our environment we have the Vault site running in it’s own app pool to isolate it from other sites. This has allowed us the ability to recycle the app pool for that site without interrupting service on our other production sites. After recycling the app pool the Object reference not set to an instance of an object goes away.
Issue
A file that a user has permissions to view in a folder is not showing up in the client application. The file is checked in and other users have no problem seeing the file. The user who cannot see the file through the client application (or any of the plugins) usually CAN see the file if they go to the Vault web-site an navigate to the file through that method (this also confirms that it is not a security issue).
Solution:
The local cache for that specific user on that machine is out of sync (the cache is saved in that users profile on that machine). From the client Click Tools->Options->Local Files->Cache Location->Open Cache Folder then delete all of the contents from the Explorer window. Close the Vault client while this is happening. When the file deletion is complete (this may take some time if there are a lot of files) restart the Vault client and navigate to the location of the missing file.
Articles used for research: