Xcode 16.3 Beta3: Developer Documentation Indexing does not end...resulting in Xcode CPU Usage high over long time.

Developer Tools & Services Xcode
B347 OP
Created
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macOS Version 15.3.2 (Build 24D81)

After initiating via Shift/Command/0 the Developer Documentation Window, the indexing of v277 index structure is starting /Users/[name]/Library/Developer/Xcode/DocumentationCache/

==> but unfortunately not ending!

Activity Monitor reports during hours high CPU (~80%) for Xcode process, but the indexing does not stop or end.

After hours it is still around 146 MB instead of about 550 MB as in previous releases. Indexing starts with 11 or more threads, but suddenly it drops to 10 threads and seems stopping, still using cpu.

Also restarting Xcode does not help. Process restarts but after some minutes seems to hang or stuck around 200MB indexed.

Also removing subfolders does not help. (NSOperatingSystemVersion(majorVersion/ 16, minorVersion/ 3, patchVersion/ 0)

  • they are recreated but index still stucks after some time.

No clue. will reverting back to 16.3 beta2 Reported via FB16926964

Answered by B347 in 837391022

Fixed (as least to my config/situation).

Note: Reverting the workaround:

defaults write com.apple.dt.Xcode IDEDocumentationSpotlightIndexDisable -bool NO

**Version 16.4 beta (16F1t) // 28 April 2025 **

Xcode now behaves as it should. The 'Developer Documentation' window can be called, a re-indexing takes place (indexing takes a few minutes, during this time Xcode consumes a few CPU cycles, but so far everything is acceptable).

The indexing process is completed and a new directory has been created. /Users/username/Library/Developer/Xcode/DocumentationCache/v279

So far I have not detected any side effects or other errors. So far so good.

Replies  10
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DTS Engineer OP
Apple

Thank you so much for reporting the issue, and thanks for the bug FB16926964. I was wondering how many other developers are having the same issue.

You can see the status of your feedback in Feedback Assistant. There, you can track if the report is still being investigated, has a potential identifiable fix, or has been resolved in another way. The status appears beside the label "Resolution." We're unable to share any updates on specific reports on the forums.

For more details on when you'll see updates to your report, please see What to expect after submission.

Albert Pascual
  Worldwide Developer Relations.
mattn OP

@DTS Engineer Yes, I'm having this issue in beta 3 as well. UIKit is never appearing in the documentation at all.
mattn OP

Yeah, reverting to beta 2 fixed it. Instantly. It feels like someone built a huge concrete wall around the UIKit docs in beta 3, and poor old Xcode was just endlessly hammering at it with all its might (i.e. 100% CPU usage but no progress in building the docs cache).
B347 OP

I have just updated my feedback request FB16926964 with all the latest information regarding the missing UIKit area and described the severity and urgency as increased.

Thanks to all involved for helping with the analysis.
B347 OP

Installed Xcode 16.3 RC (Version 16.3 (16E137))

fixed: UIKit is showing up in Documentation. This is fixed. Thanks.

:-( BUT NOT FIXED - Issue with high CPU consumption >80% Xcode Process, Indexing stucked.

with Version 16.3 (16E137) the Index Directory name has changed to v278, but unfortunately same issues as with previous beta 3 (277). Starting indexing, but after some minutes it looks like stuck and the size-increase of the directories is halting. Normally (expecting from v275 16.2 is about 534MB); in 16.3 RC + Beta3 it is stopping around 61MB.

Xcode Process is continuing running with about 80% CPU consumption!

Feedback FB16926964 is updated.
mattn OP

I agree with the assessment of @B347 — the RC is spinning its wheels, unable to index the documentation and using 100% of CPU.
mattn OP

So the "solution", according to the release notes, is just to turn off this feature:

defaults write com.apple.dt.Xcode IDEDocumentationSpotlightIndexDisable -bool YES
B347 OP

oh...at least the issue was recognized. interim solution from Apple's point of view.

I am running 16.3 RC Xcode. Furthermore I copied the index from 16.3Beta2 (so I have a complete 16.3 Doc-Index, with UIKit and can work without burning CPU). No problems so far. But there will hopefully be another fix so that the error is finally corrected in 16.3.x.
imneo OP

Same problem here. Please fix it ASAP, maybe via a hotfix.
B347 OP
Accepted Answer

Fixed (as least to my config/situation).

Note: Reverting the workaround:

defaults write com.apple.dt.Xcode IDEDocumentationSpotlightIndexDisable -bool NO

**Version 16.4 beta (16F1t) // 28 April 2025 **

Xcode now behaves as it should. The 'Developer Documentation' window can be called, a re-indexing takes place (indexing takes a few minutes, during this time Xcode consumes a few CPU cycles, but so far everything is acceptable).

The indexing process is completed and a new directory has been created. /Users/username/Library/Developer/Xcode/DocumentationCache/v279

So far I have not detected any side effects or other errors. So far so good.