Perhaps you recall back in 2012 when Google caught some flack for its 10-device limit on Play Music access with only four deauthorizations per year. It was forced to backpedal and allow users to deauthorize unlimited devices, and all was well with the world. Well, until now. It looks like Google has started enforcing a limit of four deauthorizations per year once again. Support docs and the Play Music settings list the limit. That means even regular users could suddenly find themselves unable to use All Access or get to their own stored tunes.
We've been going over this and testing on multiple accounts from the US and Canada to confirm and see what sort of behavior you can expect. Basically, you're still limited to 10 total devices, but only four mobile devices can get to All Access. You have to keep under that 10 device limit each time you connect something new (or what Google thinks is new). Now that you can only deauthorize four devices per year, it's very easy to run out of deauths.
The Android app doesn't give proper feedback when you hit the limit—it just doesn't remove the item you told it to. On the web, you get a notification that says, "Sorry, you've deauthorized too many devices." You may be thinking, surely only tech writers who are swapping devices all the time will fall victim to that, right? Well, no. Play Music creates duplicate devices when you do a factory reset or install a new ROM. Sometimes it does it for no reason. One of my phones has a dupe in the device list, and it has never been ROM'd or factory reset. To be clear, Google's device list doesn't even work right. It doesn't work, and someone thought it would be a good idea to attach an arbitrary limit to how many errors you can fix.
Almost everyone who has been using Google Play Music for any length of time will have a ton of old and duplicated devices in their list. Note, the app does not tell you about the limit. As of now, it looks like those deathorizations count against you. I was able to clear one duplicate device from my list before I got locked out, which indicates the counter started sometime recently without notice (that's scummy, Google). If Google is serious about this, the next device I try to connect to my music won't be able to access it. That says nothing of All Access, which I pay for (but don't own, obviously). I suppose this might last the rest of the year, when I'll be able to remove four devices. That should last me a few months...
Google's Support docs make no mention of a way to get Google to reset the limit on an individual basis. Hopefully that exists as an option. Even Apple can manually fix iTunes authorization limits. We're going to continue investigating this and will update with any new information we get.
Update: I talked to a Google rep (after a lengthy wait) who claims they can manually reset device authorizations. Not the deauthorization counter, but all your authorized devices. According to the Google rep, after you call and make the request it takes 24 hours for your device authorizations to be cleared out. Then you log back in with your current phones and tablets. Don't take it as gospel, but that's what I was told. I'll know if it worked tomorrow. Yes, this is very, very stupid. It prevents exactly zero abuses of the system and creates a new headache for users.
Update 2: A Google rep emailed me about 16 hours after my initial call saying:
I'll be more than happy with looking into your authorized devices. Are there any immediate circumstances that would require you to frequently authorize / deauthorize your devices (repairing or exchanging your laptops/tablets/phones)?
I replied saying I simply wanted my device list reset because I was out of deauthorizations. The rep replied saying it was done, but pointed out this was a "one-time courtesy." My device list in Play Music was indeed instantly cleared out. It isn't clear if Google is being smarter about the device list now, but some people are reporting it has started detecting devices by IMEI, which should ideally stop the dupes.
We will see about that, but I'm still not thrilled about potentially losing access to my music after four new devices in a year. That's a lot for regular people, but I would wager it's not that many for many AP readers. If you try a new device or two and end up returning them because they don't meet your expectations, that's going to eat into your deactivation limit.
[Google Support – Thanks, Joseph Bass]