Registry woes - what is causing it?

August 31, 2006 7:03 AM

Windows XP Registry - What tools can be used to analyse ntuser.dat hives?

Specifically to find out what in the hive is taking up space?

I've been tasked with trying to identify what is causing a large number of roaming users ntuser.dat files to gradually swell in size over the course of 4-8 weeks till their profiles reach the limit on a network I support. The limit is 10mb, ntuser.dat files tend to be an issue once they hit 3.5-5mb. (Majority of users sit around 2-3mb and don't swell)

GPO locks down users desktops heavily, no desktop icons/files and My Documents folders are redirected to a server location.

Current theories are:
One or more badly packaged apps filling the registry with junk. (There are a few identified which fill the application data folder with cached files.)

HKCU\Software\Microsoft\Windows\ShellNoRoam\BagMRU filling with junk (after a month or so of use 50%+ of subkeys seem to be in this area - yet clearing that doesn't reduce the ntuser.dat size by a significant amount)

There is no single software package which links all the users experiecing this problem. Number of subkeys doesn't seem to be a good way of analysing where the size in the user hive is being used up - I've not found a tool which will show the 'size' of key structures of the registry yet.

Not had any luck comparing snapshots to identify a cause either - any suggestions at this point would be welcome as this has wasted two days for me already.

posted by Leud to computers & internet (4 comments total)

This might help: Offline NT password and registry editor
posted by Blazecock Pileon at 7:27 AM on August 31, 2006

I think registries only expand in size, never shrink. If you delete stuff out of a used registry, the freed-up space is re-used before it expands again, but it doesn't ever get any smaller.
posted by Malor at 7:34 AM on August 31, 2006

Have not tried it myself, but this might be useful:

Registry Space Profiler

Not sure how detailed an analysis it gives you though. And Malor, there are utilities that do claim to compact the registry, which Windows never does by default. Although Ive never seen any that compact it significantly, maybe 10% or so..
posted by Boobus Tuber at 6:48 AM on September 1, 2006

I could be wrong, as according to that program's author:

"XP automatically defrags registry hives, and you can manually do it with the PageDefrag utility from Sysinternals for NT4 and 2000"
posted by Boobus Tuber at 6:52 AM on September 1, 2006