License Manager Error -9 when external hard drive connected or disconnected

I am running MATLAB R2015a on Windows 10. I have an USB external hard drive that I have mapped to B:. When I started using this hard drive at this location (I know it is not a floppy disk drive, but I like B for "backup"), I got a License Manager Error -9. I ran activate_matlab.exe, the license was verified, and I was able to use MATLAB again. However, when I tried to run MATLAB again, this time without the external drive attached, I again got the same License Manager Error -9. Again, I was able to get a new license with activate_matlab.exe, but MATLAB would not start the next session if the hard drive was connected again. If I disconnect the hard drive and try launching MATLAB again, everything works fine. When I type vol in the command line, I get the same serial number for my C drive whether or not the external hard drive is connected or not, so I assume there is some other check the license manager does which is thrown off by my use of a mapped B drive that is sometimes present and sometimes not. Any other possible reasons this might be happening? I'm fine as long as I can connect to the internet, but it seems like a weird bug...

[Walter Roberson]

Odd. My memory is that by R2015a they had switched to using only the ethernet MAC on MS Windows.

You could contact Mathworks about this, as there is free licensing / installation support.

Answer 1

[Peter Ladlow]

This is a long standing issue with MATLAB licensing on Windows that I regularly see users run into. There was an explantion posted on this site previously, but I can no longer find it. Essentially it is an issue with low-level Windows functions such that if B: is mapped to anything that is not a floppy drive it can result in MATLAB licence manager failing to detect a standalone licence on your PC. The workaround is simply not to use drive letter B:.