I have this same problem. I am on the latest version (1.3.1260).
This drive is NOT a mapped drive, but is an external hard drive.
I used this for a few searches and it worked great. All of the sudden the app crashed, and when I reopen it, I get the “Drive E do not exist” error, despite having selected the E: drive from the dropdown path.
It is definitely there, but for some reason the app thinks it’s not, and nothing I can do that I’m aware of can reset that or make it search the directory again.
What can I do??