Just to note, and by no means is this a common issue I’ve seen, but I recently had the SD card I had in mine (a legit Samsung card, 512gb) just randomly corrupt itself so all the games installed on it couldn’t be seen by the Steam Deck anymore. That also lead to a bonus issue where the Deck thought the games where still installed whenever I tried to reinstall them and them not booting once they had been reinstalled, and at least one of them games (once I fixed that problem) still occasionally needs me to verify the installed files so it can reaquire one before the game will load

It didn’t actually show up in the list of libraries, that was my first thought, and that was when I ended up messing with libraryfolders.vdf. Just outright removing that external drive from there had Steam just restore it after a reboot. Removing all the entries from that drive at least stopped it warning me that the game was installed on a different drive.

I seem to have fixed the issue, for some reason the cloud sync was screwing with the installation and clearing out a file related to it fixed it. Thanks for the idea though, on the off-chance this comes up again - because I’m not likely to trust an SD card in it again - I’ll look into it

Yes, the card appears to be dead, I’m trying to install the game to the internal storage now and it won’t install