Missing media error dialog. In the mapbank folder you should see your mapname.fpm, yourmapname.bak. yourmapname.dat, and a text file with yourmapname.log.
Make a copy of all of them and set them aside.
Rename the original mapfile to anything.
Chang the file with the .bak to .fpm and then see if you can reload your map.
But first open the .log file one and see what it thought was missing.
RIP
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit, Screen resolution 1680 x 1050.
New:
Intel(R) Core(TM) i5-8400 CPU @ 2.81GHz, 12GB RAM, Nvidia gtx1050ti 4gb, Windows 10 Home 64bit, Screen resolution 1920 x 1080. System Passmark 3774