From a recent email:
I'm upgrading a client from v8 to v10...they have four databases but two are "old" (never upgraded to v8 when previous VAR moved them). I plan to drop these test databases and possibly make new ones BUT I want to remove the names from the login screen drop-down since nobody can access them anyway. Do I remove those records from the DU00000000020 table or someplace else? I am not sure...can try it on their test box but figured you might know.
This isn't 'my area', but it sounds like you have two current companies, and two old ones. How about taking a good company, backing it up, and restoring it on top of the two 'bad' v8 companies. That'll give you four good companies. Then, you can remove them from the tools inside of Dynamics without worry.
I'd only edit DU00000000020 or DYNAMICS..SY01500 as a last resort...
I routinely get databases in the office from customers, to do VS Tools or eConnect work. I user DU00000000020 to find out what version the client needs to be to open up the db.
Can't you also remove the name from the login dropdown by removing access to the company in security?
HTH...