iPad Pro 2021 (11 inch) Won't Connect to iMac with Thunderbolt Cable

I feel your pain. I'm having this issue, too. USB2/3 works; Thunderbolt does not. It's been weeks, and I've been on chat or phone with Apple Support for HOURS about it.

It's the same with my 2018 Mac Mini and my wife's 2019(?) MacBook Air (both are Intel Macs… maybe that's relevant?) — it's the same with four different Thunderbolt cables, including TWO different Apple Thunderbolt Pro cables because Apple Support had me swap one out suspecting that it was defective — and it's the same with both of the iPad Pro 2021s that I've had because Apple Support replaced the iPad assuming that the iPad was defective.

But here's the interesting thing: the replacement arrived with 14.5.1 installed, not 14.6. And when I first connected the replacement, THUNDERBOLT WORKED. But all my data was locked in a backup, so I needed to update to 14.6 — and in the process it did a firmware upgrade along with that. And after it updated… it didn't work anymore. So it is VERY very very very obviously NOT A HARDWARE ISSUE. It's either 14.6 or the firmware upgrade that "broke" it.

And I'm having a very hard time getting Apple Support to recognize this and promise a fix FAST, because this is some really basic functionality.

I’m trying to figure this out as well with my 2021 12.9” iPad Pro. I had previously purchased a few USB4/Thunderbolt 3/Thunderbolt 4 cables from cheaper brands in anticipation of getting my 2021.

The cables worked for data in USB3 mode with my 2020, but simply wouldn’t connect my iMac to my 2021 (like you said, only work for charging). Worse, if I powered on the 2021 by plugging it in via Thunderbolt cable, the port would simply die after I unplugged it, and require a reboot before it worked again.

I went and bought an Apple Thunderbolt 3 cable just to rule out my third-party cables, but same thing. Connecting with a regular USB-C (either 2 or 3) cable works just fine for data.

There have been a number of reports of specific Thunderbolt 3 SSDs also not being recognized at all by the 2021 iPad Pros, even though most of them seem to work fine (albeit extremely slowly). This appears to be a software problem with iPadOS 14. For now, you’ll have to keep using a regular old USB cable until Apple can finally fix this.

On a side note, I’ve just spent 20 minutes with an incredibly clueless, rude and impatient Apple support representative, who cut me off instantly to try and kick me off to a different department. She had no idea what Thunderbolt even was, and was unaware that iTunes no longer exists. She kept insisting that I “plug it in to iTunes instead of Finder,” cut me off when I tried to ask if she meant the Music app, and kept telling me that my iMac had 4 USB ports (never mind the fact I had already told her over a dozen times my issue was with Thunderbolt, and that USB worked fine). Then she again tried to kick me off to a different department.

My experiences with Apple support over the past 3–4 years have all been a complete waste of time, and I’m quite confident to say that Apple now has the absolute worst customer service in the industry, by a pretty wide margin. They always go for the most disruptive solution (make you wipe your device and tell you to set it up entirely from scratch, because “software corruption”), and refuse to replace a device in perfect cosmetic condition that exhibits intermittent, hard-to-reproduce issues, just because hard-to-reproduce means it can’t possibly be a hardware problem.

[Edited by Moderator] 

You have presumably attempted to sync your iPad with your Mac using a standard cable? Whilst the new iPad Pro does indeed support USB4/Thunderbolt3, your cable may not provide the necessary connections; cables do necessarily support all services.

As described, yes, you might anticipate that the combination should work. However, at least a diagnostic exercise, you would be well advised to verify connectivity between iPad and Mac using the cable supplied with your new 2021iPad Pro.

On the off chance of a mistake having been made somewhere along the line, are you absolutely certain that you have a 2021 iPad Pro 11” - and not the previous 2020 model?

Actually, I spoke too soon: my USB 3.2 (Type-C) cables, which had worked fine with my 2020 iPad Pro, no longer work with my 2021. Just like the Thunderbolt cables, they only work for charging, and do not show my 2021 iPad Pro in Finder or System Information.

Have you tried with a non-Thunderbolt, USB-C 3 cable?

I wanted to update, because there have been some developments. I may have been wrong! It may have been a hardware issue, after all? The fact that my replacement device worked with 14.5.1 MAY have been a coincidence (the one and only time I tried it before restoring from a backup and updated to 14.6). Because: when I brought the replacement iPad Pro into an Apple Store, the person there we realized that the replacement's Thunderbolt DID work — with 14.6 — occasionally. A bit less than 50% of the time, the iPad would be recognized by the Finder (which suggests hardware, not software). Jiggling the connection didn't seem to help (or hurt), so it wasn't purely a loose port situation. (And that wouldn't account for USB 3 working every time, anyway.)

So I just received a SECOND replacement through the Apple Store. I asked to test this one out before I left — and sure enough the Thunderbolt port on this one has worked every time, both in the store and at home now. But it also has 14.5 installed… and I'm afraid to update it to 14.6 just in case that was (part of?) the problem.

I'm going wait a bit before updating to 14.6 so I can be absolutely sure that it is 14.6’s fault if it does break again. But in the meantime, it's working.

Aaaand 14.6 broke it. Thunderbolt worked flawlessly in 14.5. I plugged it in and unplugged it dozens of times, transferred data super fast. It was lovely. I restarted the device more than once.

And then I updated to 14.6 so I could actually access the data locked away in my backups, and it was broken again.

I'm so freakin' mad right now. Apple Support has wasted so much of my time and money over this issue.

Yeah, it’s a USB 2 cable. USB 2 still works fine.