Quote from: kryptopojken on August 27, 2017, 01:10:31 AM

Bounty raised to $30 for anyone who solves my problem

I can't solve the problem completely, but try this:

create a dummy/empty wallet in Electrum
close your original wallet (while keeping the dummy wallet open)
close electrum completely
reopen it (now, it shows the new dummy wallet only)
go to file menu, and open the original wallet manually
Electrum will ask the PIN code of Trezor without any error message, and works fine. If not, try to close the original wallet only, and reopen it from file menu

It works for me in Electrum 2.9.3 and Electrum-LTC 2.9.3.1 on OSX.

Maybe Electrum wants to open/initialize Trezor or USB port too fast during loading of the wallet?