We had the same problem and applied ptf for 3.7.4 which allows the use of a new 
parameter (skipdirs=yes) with the 'expire inventory' command.  TSM's method of 
expiring archive files was causing expiration to run extremely slow.  The 
skipdirs parameter solved the problem.

>>> "Lau, Ming" <Ming.Lau AT LAMRC DOT COM> 04/23/01 04:23PM >>>
After the upgraded ADSM 3.1 to TSM 3.7.4,  I have similar problem which
under investigate now.  Larry, what exactly problem you have with Expire
Inventory. Missing volumes in storage pool??

Besides that, there is another problem I experienced.  The "Maximum Mount
Points Allowed" @ client node will be set to 0 after you re-set the client
node password.  Once the "Maximum Mount Points Allowed" was 0, no tapes can
be mounted to any tape drives.

Ming Lau
Lam Research