I have noticed this problem recently on my EVO as well. The data for the app itself is kept I think. It's kinda bothersome to have to restore the apps every time.

Thanks in advance for any help.
-Rooted EVO, RA-rec, Baked Snack 1.8 w/default kernel, Lowrider theme 2.5.3

 

It also happened to me today. Desire 2.2 rooted

 

is it apps that you may have tried to update while the market was having issues recently? That could cause this.

 

Some of the apps have been recently updated, but not all. I think it is because they are on the sd card. I restored two apps as you can see in the screen attached, Angry Birds and 2reactor. The rest can be selected, but the "uninstall" button is missing.

 

When the screen looks like that it means the sd card isn't mounted. Mine only does that when connected to my pc via usb drive.

I would try un-mounting and re-mounting the sd card and see if that helps.

 

Taking the card out and refitting it might be an idea too.

 

My Pandora and Slacker apps went away, as well as any Amazon store apps ( Kindle, for example ).