I've had this issue with my MBA resuming from sleep. I posted about it in the Mountain Lion section of this forum, but I am beginning to think it's actually a hardware issue, and I am looking for advice. The MBA is out of warrantee, but I have a private insurance plan that will cover major repairs. Here's what happens when I let my MBA sleep for many hours: On resume, it freezes. Sometimes pressing the power button will cause the curser to show up, sometimes I get a spinning beach ball, most of the time I get nothing at all. I've left it like this for 30 minutes, nothing. I've closed the lid again and come back 10 minutes later, nothing. The only thing I can do is a hard restart. Normally the MBA started normally after this. Lately, the Macbook Air has been booting to either a white/gray screen, or it shows the folder with a question mark icon flashing (meaning it cannot find the boot drive). I hard reboot it again, holding down "option", and it does not see the internal drive. After a few minutes, it offers me to boot into recovery, but still no hard drive. I do a hard reboot again, and again hold option. This third time it recognizes the hard drive fine, and boots into it just fine. Everything remains fine until I again leave it it in sleep for several hours. What I have tried so far: - Reset all pmset settings to default - Resetting SMC - Resetting NVRAM - Clean reinstall of OS X 10.8.2 (still happened on that version) - Updated to 10.8.3 again - Run it with filevault disabled and enabled (its usually enabled) - Messed around with various auto-login and password login window settings - Reseated SSD - Done a long hardware test - Left it sleeping after quitting Chrome I am calling on the MacRumos brain trust! Is this a software issue or a hardware issue? If software issue... I am out of ideas. If hardware, how do I test for which piece of hardware it is?