The curious incident of the freezing MacBook

I posted on Twitter yesterday about some problems I was having with my aging MacBook. For the last week or so, it seems, my laptop is locking up–freezing–several times a day. So bad is the lockup that all I get is the spinning wheel cursor and nothing works. No keyboard commands, nothing. I have to physically power down the machine and reboot.

Well! I might be a software developer in my day job, but I started out as a troubleshooter, and a pretty good one. Friends and family are often asking me for help. So why not turn those troubleshooting skills to my own problem?

At first, I thought it might be related to my external harddisk. I have a 1 TB external disk connected to the MacBook via Firewire. All our media is stored on this disk (which is in turn backed up to the cloud via IDrive). When the computer would freeze, I noted that the light on the disk (which is a kind of roving white light akin to the roving red light that characterized Michael Knight’s car, Kitt in Knight Rider) was frozen as well, as if access to the disk was causing the problem. I ran some checks on the disk but nothing turned up. The disk, at least according to the disk software, is in good shape.

Well, maybe it was the connection to the disk. Maybe the cable was bad. One way to tell for certain would be to shut off the disk and disconnect the cable and see what happens. I did that. It seemed to work at first, but before long, the computer would lock up again. The lock-ups seemed arbitrary. No one thing was causing them.

I began to explain this to Kelly last night, worried that it might be time for a new computer. (Worried because I really don’t want to spend the money on a new computer right now.) She told me that she’d been having the same problem with her computer recently. She has a newer model of MacBook than I do. She thought maybe it was our Internet connection. I doubted that but in the back of my mind, something stirred. It was odd that both computers would be acting up at the same time.

I went back to the basics: what changed? I asked myself.

I keep a notebook in Evernote called “Timeline” in which I record notes of various things that I want to keep track of. When the Little Miss first smiled. Who I voted for in the last election. I also drop in notes about changes I made to the computer, software installs, updates, etc. I took a quick look and was reminded that I had used a little hack to enable AirDrop on my MacBook. And I had done it nearly a week ago. My MacBook is too old for AirDrop to appear by default but this hack makes it available in the finder. Indeed, when Kelly’s computer is on, I can see her computer in AirDrop. And that’s when it dawned on me: she is seeing the same problem as I am. Could it be that enabling AirDrop on my computer is causing the problems on both, since AirDrop on my computer would be trying to talk to her computer and vice versa. And while AirDrop is enabled by default on her computer, it isn’t on mine. And maybe for a reason…

So yesterday at around 6pm, I disabled AirPort on my computer. I proceeded to do my usual work (fiction writing and blog posts) without any lock-ups (after rebooting my machine 4 times in the space of an hour before Id’ disabled AirPort.

For the last week, when I get up in the morning, inevitably find my computer locked up. This morning, it wasn’t lock up. The external drive was connected all night and the machine was just fine. I think I need to give it another day or so to be sure, but I now believe that AirPort was the culprit.

Furthermore, I suspect (but have not verified) that the lockups on my machine coincide with times when Kelly had her laptop open (she often shuts her laptop down; I never do) and AirPort was actively trying to talk to the other machine.

I’m cautiously optimistic that I’ve solved the problem, and can put off worrying about buying a new machine for a while longer.