I upgraded DOCman and it says all files don't exist!

The most common issue here is you have changed the download folder and failed to backup your configuration file prior to upgrade, thus DOCman is running on its default config. IF you have changed the upload folder to say "downloads" then DOCman by its config is looking in dmdocuments - since all your files are in "downloads" - it cannot see the files.

Change the folder back to "downloads" on the DOCman configuration and all files will now be listed as present as they were prior to updating - no information is lost during upgrades!