10.5.5, v.3.1.3 of Media Composer... 

Editor reports that he worked for hours, then wanted to undo...  His undo list only had the last event...

He claims this has happened to him before.

I trashed MC State and replaced editor settings with a copy.  Hasn't happened again today...

Just curious -- anyone else experience this?  Known bug?  Workaround or fix?

I had the same problem in MC 2.8. It was a recurring settings issue. One day, it never came back.

Hi,

Just to make sure, if you load another sequence and start working on it, then go back to the first one, your undo list will be reset.  In other words, the undo list doesn't get saved if you switch sequences and then switch back.  That may not be what's happening in this case, but it's best to check before looking for problems.

good luck,
Carl 

Other than what described above, settings do get corrupted which is why trashing composer settings and/or user settings are often times recommended why troubleshooting

Yes, this is a frustrating issue.  I have experienced this many times after editing for awhile, particularly on complicated sequences.  It seems to be more of a memory leak type issue than a corruption problem (I'm just guessing here, don't quote me on this).  Exiting the application and relaunching the software restores the functionality of the undo list but does not help restore the "lost" undo list.

money's on a memory leak.  and the complicated-er the worse-er.  and the more apps going at once the worse-est.