Newbie here, would very appreciate any input you might have. Running 2010 macbook pro, initially with 2+2GB ram. Upgraded HDD and installed 4+4GB ram 2-3 years ago without problems 6 months ago began having kernal panics causing forced sleep. Was unusual because I could not wake from sleep no matter what. Had to manually shut down. Was initially once every 2 weeks but began occurring daily. Initially I thought this was a software issue. Was lazy and had not upgraded Snow Leopard because was getting close to filling HD. I upgraded HD, ran disk utility, which didn't show any problems. Then upgraded to Sierra (my system is compatible) and all updates done. Ran disk utility again and HDD ok. But still having daily shutdowns, can occur with any variety of apps, can happen 1 minute after start, or 20 minutes in. I doubt related to temp because can happen right after starting or waking from sleep. Before I fresh installed macOS and software, wanted to make sure was not a hardware issue. Ran Apple Hardware Test which found no errors. Ran memtest in single user mode which found no errors. Then ran memtest86 which gave me the following: Errors: 65535+ Error Confidence Value: 18 Lower Error Address: 000ae000000 - 2784.0MB Higher Error Address: 000affffffc - 2815.9MB Bits in Error Mask: ffffffff Bits in Error - Total: 32 Min: 1 Max: 32 Avg: 18 Max Contiguous Errors: 65535+ I re-ran memtest86 with stick 1 alone in slot A, then in slot B. Then again with stick 2 alone in slot A, and in slot B. ALL 5 tests gave the exact same results as above, with the same exact addresses. Based on this, it is the motherboard? What's my next step? I know my system is old, but I would like to hold off upgrading until the next round of iMacs. Thanks very much for any advice you could give!