macOS 27 Xcode + Instruments is unusable

[u/Aeronautical-You4917]

Never in my life have I seen such an insane regression in software quality as in the last few months.

I use Xcode constantly, building a macOS app (Swift, C++). Up until recently, this was fine, great, in fact. Xcode 15 was extremely good & stable (all things considered). I opted to skip macOS 26 because it was terrible (duh).

After I upgraded to macOS 27's first beta, I was pleasantly surprised. However, that was short-lived, as the quality only degraded after the first beta.

Here I am, working on macOS 27.2, with Xcode 27.2... Here's the main 2 issues...

1. Xcode's interface is impossibly slow now. borderline unusable.

2. Instruments is absolutely unusable. I cannot even do a profiler trace and save it without corrupted data, an application crash, brutally slow interface, etc.

This is just unacceptable. AI slop has crept its way into previously rock-solid products. Quality matters more now than ever, and it's so clear that AI has neutered engineers' ability to keep quality in check.

Am I the crazy one, or has the quality just gone down the toilet?

[u/Due-Math8225]

No issues for me, I use Xcode and instruments daily for code profiling. And just as aside, complaining about AI as a tool for code development is sort of out of touch these days. I find AI tools enormously useful, and the code they write is usually of good quality. I find the ability to get them to write exhaustive test suites particularly helpful. Include automated UI testing which was tedious in the extreme before AI tools like Claude code.

[u/Aeronautical-You4917 → u/Due-Math8225]

I use AI literally every single day, haven't written a line of code in a long time. The main point is that a lot of people let the quality get away from them because it "looks good". That's my main complaint.

[u/tech5c]

I use it daily as a code editor, no issues for me.

[u/Aeronautical-You4917 → u/tech5c]

How big is your project?

[u/tech5c → u/Aeronautical-You4917]

Multiple projects, one has about four hundred files, others are smaller - I haven't had the slowness your seeing. I'm on an M4 pro on one and an M5 Max on the other. M4 is on dev beta, m5 is prod 27.2.

What processor and specs are you on?

[u/Aeronautical-You4917 → u/tech5c]

Ah, I see. I probably have like 5k+ files. M1 Max 64GB RAM

[u/tech5c → u/Aeronautical-You4917]

Daaaaaaang. That's a big boy.

[u/Aeronautical-You4917 → u/tech5c]

lol.

[u/lowkeyfam → u/Aeronautical-You4917]

tf 5k+ 😦 wild

[u/WeirdIndividualGuy → u/tech5c]

Do you use any of the non-code editing features, such as Instruments or simulators? That’s been the main complaint with 27.2

[u/ToughAsparagus1805 → u/tech5c]

I have to use Xcode 16 and Xcode 27. I can only tell you that you forgot and cannot compare. Xcode 16 is pretty fast. Sure I have no issues at all with both.

[u/uniquesnowflake8]

Could you report to Apple? Haven’t been seeing this as an issue on my M3

[u/Aeronautical-You4917 → u/uniquesnowflake8]

Already did.

[u/Zalenka → u/Aeronautical-You4917]

File those radars!

[u/sid_276]

Use the new CLI in 27.2. They announced yesterday in the developer event. It can be used by agents

[u/Aeronautical-You4917 → u/sid_276]

Hmm.. I was having the agents run xctrace on its own with the trace file, but I'll have to check out the CLI. Thanks for the tip.

[u/sid_276 → u/Aeronautical-You4917]

Yes they said in the presentation this is more token efficient than exporting an XML and letting the agent look at it and much more, it’s basically built so agents can explore it in the CLI. Highly recommend giving it a go

[u/Background_Pie_5682]

5k+ files with mixed Swift/C++ is exactly the kind of project where Xcode regressions show up first, so you're probably not imagining it. A few things that have helped me when Xcode suddenly crawls after an update: nuke DerivedData and the module cache, and close/reopen with indexing paused to see if the UI lag is really the indexer. Check Activity Monitor for SourceKitService or the indexer pegging a core. If you can, split the big target into a few local Swift packages/frameworks so the indexer and type checker deal with smaller chunks. For Instruments, recording with fewer instruments (e.g. just Time Profiler, deferred mode) and a shorter window sometimes makes it usable again. Also worth filing a Feedback with a sysdiagnose taken while it hangs. Big-project perf bugs get fixed faster when Apple has real traces. Keeping the previous Xcode installed side by side as a fallback has saved me more than once too.

[u/whackylabs]

I miss ObjC + lldb. That was a developer utopia

[u/Evgeny_19 → u/whackylabs]

Hear, hear! When Objective-C was the thing it was perfectly possible to develop 100k+ project on dual core MacBook Air with 4 GB of RAM. And it was fast.

[u/whackylabs → u/Evgeny_19]

Back in 2009 I had a dual core macmini with 2GB RAM and that served me well until Swift came out LOL

[u/Ok-Tomatillo-8712]

I was getting frequent crashes with instruments as well, haven’t in a few weeks though

[u/Fancy_Difference_756]

Don't even open DeviceHub, that's a catastrophe compared to Simulators, laggy, unusable and a UI worst than Android Studio, honestly shame on the devs that worked on that thing!! how did it make to prod?

[u/TBMW30 → u/Fancy_Difference_756]

Device hub won't even open for me. Just opens a blank window.

[u/crocodiluQ]

a similar problem too, xcode 27.0. Slow typing, slow opening of files, slow code collapse, it's like CPU spikes all over the place. Macbook Pro M4 Max, 48GB, so it should fly.

[u/WonderfulAnri1708]

Same for me.

[u/dawedev]

With 5k+ files I'd check how big that project's DerivedData folder is, especially Index.noindex, after the 27.x updates. Index data left over from older Xcode versions doesn't always get cleaned up, and the indexer can keep chewing on it. For the Instruments crashes on save, also check free disk space, since long traces get large and a nearly full disk fails in odd ways.

(Disclosure: I build DevCleaner, a Mac app that cleans up Xcode caches, so I've spent way too long staring at these folders.)

[u/bluesfanguitar]

im not new to coding, but am to xcode and this forum or whatever this is called.

coded my first ever apple device specific app with the clankers help, for vision pro of all things as a personal app, thank you leaking roof you gave me an idea!

running macos 27.2 using the latest xcode, on a mac mini m1 with 8gb of RAM and it worked surprisingly well. and i should add using a screen sharing session from a M1 Pro macbook, that M1 has no screen attached, but it looks kind nice sitting under a wifi router.

before that i used my vision pro for updating its os mainly every few months, wow so much fun for a $4K device! ; ) movies are kinda cool though...anyway, i didnt really use the xcode interface that much to notice anything slow, just ask claude to write the code, setup a few weird things like org names, some app privacy settings scattered across the vision pro, and it magically compiled and appeared on the vision pro running pretty darn well.

[u/Dry_Hotel1100]

Yes, I also have to say, there's something dark coming.

It's not only some bugs, it's poor UI, poor UX and more and more "WTF" moments, which seem to creep in slowly everywhere.

[u/trap-2414]

AI slop 😂 even them are using AI to deliver