Sign me up on the list of users experiencing the Assertion Failure M: Drive path error. I just tried to upgrade today.
Steps taken during upgrade:
1. In previous latest v3.2.5 MM went to File>Maintain Library. Let MM do it's thing, and then closed out MM.
2. Backed up MM Install folder files, dB file,MediaMonkey.ini, entire music library to a separate HDD.
3. Installed MM v220.127.116.116, over the top of previous version. (Now that I found this thread, this sounds like where my mistake happened. Also note, that's the Default install location that the MM v4.0 installer gives you. My thought in doing that, is that is probably what I wanted to do, since that's where all my scripts are located and didn't want to have to go through re-installing scripts also.)
4. Saw the Assertion fail error right after MM installer performed the MM.db update process.
5. Ran MM v18.104.22.1686 and I receive the Assertion Failure error anytime I click on the "Music" node, where it won't expand and show my music library.
The strange thing is, is that although it seems like MM v4.0 is not finding my music library, if I click on my Playlists which were created in v3.2, they all appear and the music files in the playlists show up and playback with no problem.
From reading this thread now, it sounds like a work around solution would be to replace my database file with the one I backed up.....but here's what I ended up doing instead.
1. I went to the "My Computer" node in the MM browser and browsed to where my music was located.
2. I browsed to a folder which contained "some" of my music files, right clicked and selected "Add/Rescan Tracks to Library".
Here's a picture of the folder I chose to do the Rescan....Note, I decided not to do an entire Rescan of the top "Music" folder where my entire Music for my library is located, since I have over 10K songs. This was more of a test to see what would happen.
Here is the Rescan Message that MM provided. Note....MM added my entire library of 10K+ songs, although I didn't ReScan the folder that contained all my songs....which would have been the top level "Music" folder shown in the tree view. I just Rescanned the "Oldies" folder which only contains 271 Songs of my 10K+ library.
3. I then restarted MM.
So, add this as a work around for anyone experiencing this problem. It seems much easier than replacing your MM.dB file. Especially, if you didn't happen to back it up before the upgrade of v4.0.Work Around Steps:
1. Goto MyComputer Node in MM
2. Browse to a folder which contains some of your music files.
3. Right Click and select "Add/Rescan....."
4. Restart MM
So now, I am no longer getting the Assertion Failure error message when I click on the Music Node, where my entire music library now shows up when I click on the "Music" node.
The only error I'm getting now, is when I 1st start up MM, it gives me an error which seems to be tied to the "AdvancedDuplicate Find and Fix" script.....
I tend to use this script quite often. So....off I go now to try and find a thread hopefully with that discussion and a solution for a work around.