(Update September 2011: I have no idea if any of these sticks are compatible with Lion, but I’d guess not. I definitely wouldn’t install the file linked below on Lion, it will almost certainly make things worse.)

Problem: If you install the software supplied with this stick on Mac OS X 10.6 (Snow Leopard), your Mac will hang when it is next rebooted.

Cause: The installer replaces libcurl.4.dylib with it’s own version, which doesn’t have a 64-bit version available. Pretty much everything uses libcurl, including the LoginWindow, so you can’t get into your Mac.

Solution: Replace libcurl.4.dylib with the version originally supplied with Snow Leopard. If you’ve lost yours, you can download mine. Unzip it and put it in /usr/lib – replacing the version already there. If you can’t boot your Mac, you can do this in target disk mode from another Mac, or use single-user mode.

After replacing the file, your Mac will boot, and yes, the stick will work.

Note: This is a complicated procedure, so if you don’t understand it, please ask someone else to help you. I cannot.

P.S.: Did I save your computer? Here’s my wish list. ;)

Update 17/10/09: A friendly commenter told me that T-Mobile UK, unbelievably haven’t heard of the problem. It’s bad enough that they didn’t bother to test any of the pre-release versions of Snow Leopard which were available for months before it was actually released – but it’s utterly inexcusable that they haven’t even bothered to try it after it was available in the shops. T-Mobile: If you’re reading this, this page has had over 2,000 views this month alone. I offer you the chance to respond publicly, here. Email me, my address is in the sidebar.

Update 20/10/09: Paco Hope has done a very good summary of how poor the ZTE software is. I agree with him.

Update 21/10/09: I contacted T-Mobile UK and asked for an official response. No response was ever received.

Update 27/10/09: Commenter Rafal Grabczewski has very kindly provided updated drivers that work with Snow Leopard, direct from ZTE! You can download them here. I haven’t tried these yet – so let me know if they work for you! – Maybe not, see comments below.

Update 27/11/09: T-Mobile have now posted a tiny warning at the bottom of this hard to find page – but still haven’t done anything about actually fixing the problem. Amusingly they say the stick causes “serious system instability”. Well yes, I suppose “not working at all” is a kind of instability. Sort of.

Update 23/3/10: Sticks bought recently have stickers on that say “Now 10.6 compliant”. I haven’t actually tested one, so I don’t know what has changed, or whether it’s possible to update an existing stick.