These are some of the common problems people encounter when using M64MM.
M64MM straight up doesn’t start!
This could be caused by many things.
Make sure your Antivirus is not blocking M64MM. Sometimes antivirus software think M64MM is a virus and send it to quarantine. Google how to remove a file from your antivirus’ quarantine if you suspect this is the case.
Rightclick the M64MM.exe file and go to Properties. Check if there is an “Unblock” button. If it’s there, click it and click OK. This happens sometimes with programs downloaded from the Internet.
M64MM cannot find base address but my game is open!
Make sure you’re using a USA (NTSC), non-byteswapped SM64 ROM. Its name is usually
Super Mario 64 (U)[!].z64. (Note it HAS to be Z64.)
This could also be caused by Project64 being a ghost in the background. See here for a solution to that.
M64MM says “Failed to open Project64!”
Make sure Project 64 is not running as Administrator. This will make M64MM not able to edit PJ64. On that note, don’t open M64MM as administrator either. (This is why you should not extract M64MM in Program Files.)
M64MM opens and finds the base address, but it does nothing in my PJ64!
You may be having a second PJ64 running in the background. Modern versions of PJ64 will ask you if you wish to terminate the PJ64 in the background when you open it again, but if you use a version of PJ64 before 2.0, you will encounter this. To fix it, go in Task Manager, go to More Details (Details tab in Windows 7) and find in the whole list a process called “Project64.exe”.
Then, right-click it and click the button that reads “End Task”.