Adding Non-Steam games to library [Problem]

It has happened to me too

Yeah, it happens from time to time. You can make a backup of "shortcuts.vdf" and restore it when it gets corrupted.

It happened to me too. Also some games marked with "install..." while they're already installed. A recent update might be the cause.

I thought that was just me, but it happened to me after a few recent steam client updates. Seems ok after last update.

I also had this problem a few days ago. It hasn't happened yet after I exit steam by clicking exit. Before I would just shutdown my pc.

If it's really a problem for you, you might wanna consider opting out of the beta for a while to see if that helps,
it wouldn't surprise me if the beta patches are the reason your library resets that often, since those patches are experimental in most cases.
If it still happens then at least it won't happen that frequently, since the beta updates almost daily.

-edit- Considering your post above this one it's likely that you're corrupting the related steam files

If you turning off your computer, close steam first (wait some 5-10 sec) and then turn off computer
it's working for me

Yeah, I had that problem with GW2. At the end I got tired of adding it everytime I tunred on my PC

It has only happened to me once, but I only had 2 non-steam games at that moment and I don't remember the circumstances.

Do the custom images disappear from the folder?
Steam-userdata-some number-config-grid

It happened to me too and it's kinda annoying.