Hi, I have been using Desmume 0.9.10 for about a week now, running Pokemon Black 2 all from an external hard drive (forced to be the F: drive) that I use on both my Windows 7 PC and my Windows 8 laptop. I have been intermittently been using both machines and Desmume has been running fine from the external hard drive, except for today where Windows 7 failed to remember the default program for the .nds files (which it had auto-assigned Notepad++ to). I tried to change the default program like this person did (see link) and I am receiving the same issue. I have not updated any drivers since using Desmume (and I have not used any other DS rom previously). The unusual thing is, Desmume is happy to access the file through File --> Recent ROMs, but it does not add itself to the Available programs list in "Open with" menu. I safely removed the external hard drive from the Windows 7 machine, fired up the laptop and double-clicked the Black 2.nds file from the windows file explorer and it opened it in Desmume 0.9.10. I have googled this for the last few hours now, but I have not found another person with this problem (aside from the link below, which remains unresolved from 2010). http://forum.romulation.net/index.php?topic=49838.0 Thanks for your time, Kind Regards, Matthew Post Merge: [time]1411784998[/time] I fixed the problem! My Windows 8 machine changed the drive letter of the external hard drive that the emulator and .nds file were on (I forced the drive letter on the Windows 7 machine), and when I loaded the external hard drive on the other machine, it must have reassigned the drive letter, thus breaking the link to the desmume.exe file. Assigning the letter drive to the same letter on both machines fixed the problem Edit: Is there any way or marking this thread as solved?