I seem to have this with every single update. My theory: You install Evernote and it stores the evernote.msi somewhere, which you will need at any point you want to uninstall/upgrade. It puts it in your temp folder so if you ever, quite rationally do a cleanup, it's gone. You get a notification that there's a new version and you click the ok to proceed. The updater downloads the new msi, which is also called evernote.msi, and puts it in the same place as the old evernote.msi, overwriting it if it still existed, and therefore not even making it available in the recycle bin. The installer then goes to uninstall the old version using evernote.msi, but it's a different version of the msi and cannot proceed. You quit, reopen Evernote, find the exact version you have, enter that in google and hope you can find an evernote.msi for that exact version. If you succeed, you are lucky. Otherwise you find some sort of cleanup utility to remove all traces of Evernote from your system, then download the new version and install. You make a note that next time you're going to make a copy of this particular evernote.msi for next time this happens, but you don't. .... you eventually find that filehippo keeps older versions http://filehippo.com/download_evernote/60652/ Now to see if that will let me do anything.