Please bear with me, I know there are a lot of threads about the same problem but I've tried everything suggested in them to fix it and nothing has worked so far.
I used to use an S7 (Android 7) on my private Win 7 PC and set up a Win 10 workstation a couple of weeks ago that I've been using since. Since then, every time I connected the phone to the PC, it displayed a message on the phone about giving permission to use the MTP connection (Which it only did once on my Win 7 PC) and then debugging was working just fine.
Yesterday the phone didn't show that message and Eclipse also didn't detect it (it didn't show up in the "Devices" tab), I had to restart the PC to get it to work again (restarting ADB,.. didn't work). Today even restarting the PC didn't help.
What I've tried so far:
- Restart the S7
- Restart the PC
- Kill and restart ADB (through Eclipse and command line - said "daemon not running; starting now at tcp:xxxx", then "daemon started successfully" every time)
- Disable and re-enable Developer Mode
- Disable and re-enable USB-Debugging
- Change connection mode to PTP and back to MTP
- Set to "always prompt to pick device" instead of "automatic" in Eclipse (Run - Run Configurations - Target) - it's now back on "automatic"
- Different USB port
- Different USB cable
- I installed the Google USB driver through the SDK Manager when I started using Win 10 but Eclipse stopped detecting the S7 after restarting the PC, so I uninstalled it again and have been using the driver Win 10 found since then (and, like I said, everything has been working fine until yesterday)
- Install Kies (it told me to connect a phone, even though the S7 was connected)