Yes - I have searched for this - and found no solution that worked for me. That said:
Roku 3, I added a 32G memory card. My remote, upon adding the card is no longer detected.
I loaded the Roku app for my smartphone to be able to select to format the SD card - and it still is not recognizing my remote. (There is no "pairing" button inside the remote).
I did use the smartphone app to scroll through to re-connect to the remote. Doesn't recognize it.
Then - used smartphone app again to go to System > Restart Roku - and it's been stuck on the startup Roku screen for about 10 minutes, now - and is not recognized on my network, yet to be able to use the smartphone app.
What gives? Can't these things just work as intended?