For those of you using the “automatic” feature of getting a local file, you need to take a look at your default location where Revit dumps the local files. Like my two boys, Revit does a poor job of cleaning up after itself. Over time it can start to fill up your hard drive, which can lead to bad-ness.
Just by taking a look you should be able to figure out what file is what. Be sure to delete old unused local files, as well as their corresponding BACKUP folders. You will most likely need to scroll “up” to find the BACKUP folder, but they are huge too. They will start with the exact same name of the local file, so be sure to clear out the right ones.
You can find your file location by going to Revit Options and checking out the File Locations section. The “Default path for user files:” is where Revit sticks all those local files and backup folders.