I only asked because I've had issues on MacOS before where it installed from an external device but as soon as I ejected the device, it "disappeared" 
Other than that, no idea why it might of vanished... Did you just try reinstalling? Backup you wallet file to be safe, but it shouldn't overwrite it

Other than that, no idea why it might of vanished... Did you just try reinstalling? Backup you wallet file to be safe, but it shouldn't overwrite it
I re-istalled and it works.
