I have a Samsung Galaxy S4 running Android 5.0.1. I don't know the last time I tried accessing the phone with my computer but it worked using MTP.
Now I struggle enabling MTP. The phone prompt (asking for MTP/PTP) won't appear. I double checked it with another PC so the USB port doesn't seem to be the problem.
I followed this little answer but I don't have the three dots (aka context menu) on storage settings.
My PC is running Linux. But I don't think this is the problem as the phone prompt does not appear and the device is not even recognized (no /dev/-entry). But to be sure I additionally installed
mtp-tools just to be sure. But it didn't help.
Oh. I'm using encrypted device with encrypted SD card. Does this disable MTP at all?