I have the same issue with my Garmin Smartdrive 50. i checked this article: https://support.garmin.com/nl-NL/?faq=GuclsqmdI02dC0ULxHR2T6
My conclusion is that it must have something to do with free space on c drive. I have a 128 GB SSD for c: drive an dit has only 15Gb free space. I installed Garmin express on d: drive, but apparently the updates for the navi still are stored on C drive. I cannot find how to change that...