Program shows error and does not start when default output directory is a disconnected network drive

[B-Hartmann]

MPL Data Cast 0.7.4
Windows 10

Default output directory set to network location, disconnect the network drive, start MPL Data Cast, error pops up as seen below, software does not start at all. this makes it also impossible to change the default output directory as long as the network connection is restored.

proposed solution:
Implement a fall-back to an available directory (user home dir?) when default output directory is not available (OSError).