There appears no way to maintain access between OS installs to games kept on a separate drive/partition.
After a clean OS install on paritition 1, the newly installed itch client is pointed to an already existing itch library on partition 2. Although the pre-existing library folder is added as the new default library folder, the itch client is unable to "see" that there were games previously installed therein. Newly installed games are, however, seen.
- Ubuntu 16.04 was installed on partition /dev/sda1. The itch.io client app default library "ItchLibrary" was created on /dev/sda2.
- The games "I am the Captain" and "Ravenfield" are downloaded and played from /dev/sda2/ItchLibrary
- Ubuntu 16.04 is replaced by Manjaro 16.10 on partition /dev/sda1, a new itch.io app is installed from AUR.
- The old library at /dev/sda2/ItchLibrary is made the default library, old games "...Captain" and "Ravenfield" are not "seen."
- Itch app restarted, old games remain "unseen."
- A new game, "Anchored" is downloaded. The client correctly uses the default library at /dev/sda2/ItchLibrary.
- The library now correctly shows that "Anchored" is installed. "...Captain" and "Ravenfield" though present, remain "unseen."
- Scan newly added/created library folders for preexisting itch game files.
- Add "Re-scan Library" button on top of Library page.
- Add "Re-scan Library" drop down on "Library" in "Essentials."