Scanner Epson GT-1500 not working correctly anymore

[desertman]

I'm wondering whether someone here has like me an Epson GT-1500 scanner and has some tips for my problem.

Since upgrading from OS X 10.10.5 to OS X 10.11.1 the scanner buttons don't work anymore. I can still open manually the Epson Scan application and scan from there but I cannot operate the scanner with the buttons. Already switching the scanner on does (literally) not sound right anymore. Under OS X 10.10 the scanner would, when switched on, go through some startup routine during which it also would make some noises. Now, under OS X 10.11.1, there is no startup routine and no sound.

None of the scanner buttons do anything (except for the power button that still switches the scanner on and off).

When starting my Mac with the old operating system OS X 10.10.5 (I still have this system with its original previous state on a second internal hard drive) the scanner is back to working normal.

Uninstalling and reinstalling the scanner software several times using the "latest" software (from 2014) from the Epson download page which is explicitly meant to be used with OS X 10.11 (Scanner Driver and EPSON Scan Utility v3.4.9.9) did not help.

Any ideas?

 

[desertman]

I just found out that also my other scanner, a Canon CanoScan Lide 210, does not react to its scan buttons anymore. Also with this scanner it is possible to start the scanner application (MP Navigator EX) manually and then scan. Uninstalling and reinstalling the scanner software does not help.

Additionally strange is that both scanners, when used the first time after installing the TWAIN driver and the scanner software (but not the ICA driver), bring up a window saying that the scanner would be assigned to Image Capture and asking whether I would want to change that to TWAIN (to which I, of course, agree). I never had something like this before upgrading to OS X 10.11.

Are other people having (or not having) problems with Epson and Canon scanners after upgrading to OS X 10.11? Does anybody know how I could get the scanners back to their "normal" behavior?