Hello everyone. A couple weeks ago I found a 2010 21.5" iMac set out on the curb for free. The previous owners thought it was completely dead (they wrote "CPU DEAD" on the back of it), but the problem was just a bad hard drive. I swapped it out for another drive and installed macOS Sierra and it's been great. I've been using it for various things over the past few days as I haven't decided if I'm going to keep it or sell it, and I have run into one issue.

Occasionally when I wake the computer up from sleep it decides that it will not automatically connect to a Wi-Fi network. Does anyone have any ideas as to why this might be happening? Again, it's only occasionally (maybe 2 out of 5 times when I wake it up), and it has no issues once I manually connect it. If it can't be fixed then I don't mind, as I'm leaning towards keeping this machine as a small IP camera DVR.

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Specs:

21.5" iMac (Mid 2010)

3.06GHz Intel Core i3-540

8GB DDR3 1333MHz (4x2GB)

ATI Radeon HD 4670 256MB GPU

500GB Western Digital Caviar Blue HDD (not an Apple original drive, but it works just fine)

macOS 10.12 Sierra (fresh installation)