I just installed 4.3.1 and tried to run it on my XP Pro Desktop machine, which has all appropriate patches through May 11th installed.

When I run analyze against either of my hard disk volumes (C: or D:), 4.3.1 immediately exits. 4.2.9 ran correctly to both analyze and defrag C:

I uninstalled and reinstalled 4.3.1 without any change in behavior.

4.3.1 runs successfully on my Vista Home Premium Laptop.

Thanks for you help with this issue.

Thanks to all for the help and info. 

You were right. It was just a very fragmented disk, an old slow CPU, and an impatient driver  . When I left MyDefrag run, it eventually did complete.

After defraging the disks, Analyze ran much faster.

This issue can be closed.

After successfully installing and using MyDefrag 4.1.2 on my Windows Vista home system. I installed it on my XP Pro system. I ran the "analyze only" script several times, each time it hung at about 99.6+ % complete on the first (C) of my two logical drives. The debug log (attached) indicates a problem opening the MyDefrag.dat file. This file does not exist in the MyDefrag 4.1.2 directory

The Drive is very fragmented.

I successfully ran JKDefrag 3.34 and 3.36 on this system. Before I try running MyDefrag, I'd like to both disks fragmentation state.

What is going on? How can I get MyDefrag analyze to complete so I can defrag my system?

Please let me know if you need any additional info to trouble shoot this problem.

Thanks.