Also I'm puzzled since it did not always hang with three beeps (I got a “regular“ kernel panic most recently, with that black PNG in the middle of the screen, telling me to reboot).Īlso I did a memtest, which reported no errors. However most sources agree on the fact that system diagnostics are only run at startup - so this should not happen in other modes of operation.

I googled the issue and found out that three beeps signal a RAM issue. Turn off, turn on, everything normal again.

The grey start up screen is interspersed with terminal messages repeatedly sagin '8debugger called: ', three loud beeps. This happend three or four times, every time it boots up as if nothing happened.

After a while the screen freezes and I hear three loud beaps (they repeat). I thought some process must have stopped the mac from switching to stand by and kept the processor busy, so no big deal. The MacBook was in standby (as always) but very hot (not usual). I noted the first strange thing a few days ago. My Feb-2011 MacBook Pro hangs with three beeps.

Macbook pro 3 beeps crash