When I tried to register my license, I received an error that both seats were taken. I logged in to my license account, and indeed it listed two seats used: one for my MacBook Pro, and one for an unknown device.
I was able to delete it, and register my MacBook Air, but I wonder about the second device. I’ve only ever installed DT3 on one machine (plus my iPhone).
Unfortunately, I did not screenshot it, but the device name was a random set of numbers and letters, starting with “C” (eg, something like C02HN4YU7). It said it was last used on December 07, 2020.
That date doesn’t mean anything to me. I don’t think I changed anything with DT in December (I did have some troubleshooting with DT Support in February with the new CloudKit syncing; I don’t think it’s related).
Just to chip in here (obviously do start the support ticket as suggested by Jim): in December 2020 there were a number of posts here from users noting their licenses suddenly appeared expired. Eric explained at the time that some changes to the backend had caused some licenses to become detached. I guess that might be what happened to you too.
If my guess is right, then the unknown device is you with a different (now detached) name. So - says the random person on the internet - don’t be too concerned (but checking sounds like sound security advice )
Glancing at the thread you shared, I have a vague recollection of re-entering my license info per Jim’s advice. The start date of the thread (December 08) evens aligns with when my unknown device was last seen (December 07). I bet that’s the answer.
We’ll see what Support says, but I feel better for now. Thanks!
Apple doesn’t let us get unique device identifiers (UDID)that we could use to tie your license to your device. In the past we used a different algorithm to create such a UDID and your unknown device with just a long ID as its name was one of these.
In general, removing devices from a license never cause any harm. The worst thing that can happen is that you need to enter your license code again on the affected devices.
“The strange registration, “C0…” was a double registration of your machine. This happened with a few clients. In the meantime, we have solved the problem. You did exactly the right thing, you deleted the duplicate registration and freed up one seat.”
Interesting. I recall this some time back when I looked at my account. I just checked and there is indeed 2 seats used for my license. I simply deleted the other one that I don’t recognize. I only use the desktop version of DT on 1 Mac. DT2Go is on an iPhone and iPad and those should be unrelated to desktop DT.