[Bug]: Sluggish, Spinning Wheel and high idle CPU usage.

[K-blanc]

Before submitting your bug report, please confirm you have completed the following steps

• Searched the issue is not already listed in the Issue List (I've searched it)
• Searched in the Quicksilver Users' Group for questions relating to tech support.
• Downloaded the latest version of Quicksilver for your system and confirmed the issue still persists.

Bug description

QS got very sluggish, lagging to open UI and interact. Getting frequent spinning wheel (at low-right corner of bezel Interface). Constant high CPU Usage (around 35% on idle).

Already tried erasing catalog (nothing above 200 entries), prefs, caches, app support, reinstalling and no plugins added. The issue always come back.

QS used to be blazing fast, have noted this behaviour since recent versions and Sequoia (M4).

Is there some setting or known interference to deal with? I really love QS, it's easy hierarchy and syntax but at this level of lagging it's becoming unusable.

Steps to reproduce

1. Activate QS
2. Any Interaction
3. Sequoia with M4 mini.

Expected behavior

Low CPU usage and fast response.

MacOS Version

macos 15.6.1

Quicksilver Version

2.5.2

Relevant Plugins

Same behaviour even with no plugins.

Crash Logs or Spindump

Spindump Quicksilver.txt
Quicksilver Console.txt

Screenshots

Additional info

No response

[n8henrie]

Hmm, sorry you're having trouble. I'm running a similar setup (also an M4) but with several plugins and QS idles between 0.0 and 0.1% CPU use. Thank you for taking those troubleshooting steps first!

Are you sure you don't have the Process Manipulation Plugin enabled? Only asking because I see references to qsprocessmonitor in your logs, and I thought that was dependent on having that plugin enabled (sorry, I should know the codebase better by now).

My other initial thought is double-checking the macos permissions, which sometimes have trouble with version changes of the same app bundle; I'd recommend quitting QS and then completely removing (with the lower left -) Quicksilver from your Security & Privacy system preferences -- accessibility, "full disk access," contacts, calendars, etc. then once it's gone from all of those restart it and accept the permissions pop-ups. I'm just curious if it's chugging away trying to catalog something it doesn't have access to?

If you are able, it might be informative to have you run a debug build, e.g. from https://github.com/quicksilver/Quicksilver/actions/runs/17170410329 (near the bottom).

If you run the binary directly from Terminal.app, (for example by running the command /Applications/Quicksilver.app/Contents/MacOS/Quicksilver) you'll be able to see some debug output printed to the screen. That might give a few clues about what it's doing with all those CPU cycles.

[n8henrie]

Bump.

This issue is pending a response and is blocked until I have more info. To keep the issue list groomed, I will often close these stalled issues if they go a prolonged time without a response. In this case, I will give it another week or so.

[mauritium]

I am seeing exactly the same problem (QS 2.5.3, macOS 12).

The debug version continuously outputs something like:

...
2026-01-10 19:51:35.818 Quicksilver[27620:44129056] No object found for process 0
2026-01-10 19:51:35.892 Quicksilver[27620:44129056] Reload time: 72.399020 ms
2026-01-10 19:51:35.956 Quicksilver[27620:44129056] Reload time: 63.791037 ms
2026-01-10 19:51:35.998 Quicksilver[27620:44129056] Reload time: 41.754961 ms
2026-01-10 19:51:36.326 Quicksilver[27620:44129056] No object found for process 0
2026-01-10 19:51:36.327 Quicksilver[27620:44129056] No object found for process 0
2026-01-10 19:51:36.395 Quicksilver[27620:44129056] Reload time: 66.745996 ms
2026-01-10 19:51:36.458 Quicksilver[27620:44129056] Reload time: 63.300014 ms
2026-01-10 19:51:36.833 Quicksilver[27620:44129056] No object found for process 0
2026-01-10 19:51:36.901 Quicksilver[27620:44129056] Reload time: 66.825986 ms
2026-01-10 19:51:36.964 Quicksilver[27620:44129056] Reload time: 62.932968 ms
2026-01-10 19:51:37.004 Quicksilver[27620:44129056] Reload time: 39.765000 ms
...

which is consistent with the spindump of @K-blanc. It seems the code is repeatedly running through appTerminated and _reloadProcesses. What triggers this - I don't know. Happens every few hours.

I don't have the Process Manipulation Plugin enabled, but from a cursory code review I believe QSProcessMonitor to be part of QS core functionality.

Let me know if you want more info. From the current NSLogs in QSProcessMonitor.m, I fear we don't have the smoking gun yet.

[n8henrie]

Thanks for chiming in. Do you have a spindump you can attach?

I think the No object found for process 0 are harmless; I silenced them in #3076 a few months ago, we just haven't cut a new release as it wasn't generally a user-facing issues.

I also see a lot of Reload time: (invoked by QSProcessMonitor _reloadProcesses) in my logs, but somewhat less frequently than what you've shown; sometimes multiple times per second but most often every few seconds.

_reloadProcesses is only called by reloadProcesses.

reloadProcesses is only called on startup (when processes is empty) and by appLaunched.

So I would guess that some application is repeatedly launching and crashing, causing this to thrash. Is that a possibility? Anything obvious in Console.app?

[mauritium]

Thanks! I didn't bother attaching a spindump or process sample because it's the same as in @K-blanc 's initial post. The cycles are essentially burned here inside the DispatchQueue "quicksilver.qsprocessmonitor.update":

               356  -[QSProcessMonitor _reloadProcesses] + 344 (QSCore + 231176) [0x1009a0708]
                    350  -[QSProcessMonitor imbuedFileProcessForDict:] + 108 (QSCore + 227920) [0x10099fa50]
                      349  +[NSBundle bundleWithIdentifier:] + 40 (Foundation + 49268) [0x1864cf074]

So I managed to build QS locally and am now running a debug copy that's sprinkled with tons more NSLog around the offending code. I've already found that indeed, sometimes processes get respawned at very high frequency, in my case it was a Safari rendering process (com.apple.WebKit.WebContent). I'll report once I find out more.

Another weird phenomenon that I haven't had an explanation for is that for every reloadProcesses, up to three _reloadProcesses calls seem to be executed. But I'm not very familiar with dispatch queues and multithreading in ObjectiveC.

In any case, I believe while it's not perfectly normal that processes get respawned constantly, at least QS shouldn't freak out over it. If QS spends on the order of 100 ms for every process that gets spawned/terminated, that's probably too much. Potential solutions that come to mind: actually speeding up the code, caching results (so it's faster than 100 ms), or throttling _reloadProcesses.

[mauritium]

I made an attempt at fixing this. By excluding XPC processes from the list of processes (and hence excluding these processes from triggering a reloadProcesses), I believe we are avoiding the repetitive runs and associated processor hogging.

[arvidtp]

Hi - chiming in to say there was another person running into this.

I had an issue with symptoms exactly like this in QS 2.5.3 (4046) on my MacBook Pro M4, macOS 15.7.3 (24G419). But I just found this issue and updated to QS 2.5.4 (4048) and it seems to have fixed it so far. Thanks!

[pjrobertson]

Thanks for the feedback @arvidtp , great to hear that! The thanks should go to @mauritium for the fix :)

If others can confirm that things are better with 2.5.4, then we can close off this issue.

[mauritium]

Unfortunately, I still see QS hogging the processor on a regular basis. I suspect it might have to do with e9561c7, but I am not sure, did not yet have time to study the code in detail and/or run an own debug build.

In any case, here is a sample, reduced to the essential bits:

Sampling process 43285 for 3 seconds with 1 millisecond of run time between samples
Sampling completed, processing symbols...
Analysis of sampling Quicksilver (pid 43285) every 1 millisecond
Process:         Quicksilver [43285]
Path:            /Applications/Quicksilver.app/Contents/MacOS/Quicksilver
Load Address:    0x102458000
Identifier:      com.blacktree.Quicksilver
Version:         2.5.4 (4048)
Code Type:       ARM64
Platform:        macOS
Parent Process:  ??? [1]

Date/Time:       2026-02-03 11:43:05.658 +0100
Launch Time:     2026-02-03 11:40:20.193 +0100
OS Version:      macOS 12.7.6 (21H1320)
Report Version:  7
Analysis Tool:   /usr/bin/sample

Physical footprint:         49.5M
Physical footprint (peak):  49.6M
----

[...]
    315 Thread_<multiple>   DispatchQueue_284: quicksilver.qsprocessmonitor.update  (serial)
    + 315 start_wqthread  (in libsystem_pthread.dylib) + 8  [0x1c051b080]
    +   315 _pthread_wqthread  (in libsystem_pthread.dylib) + 288  [0x1c051c360]
    +     315 _dispatch_workloop_worker_thread  (in libdispatch.dylib) + 648  [0x1c036ec98]
    +       314 _dispatch_lane_invoke  (in libdispatch.dylib) + 392  [0x1c0364404]
    +       ! 314 _dispatch_lane_serial_drain  (in libdispatch.dylib) + 668  [0x1c03638a8]
    +       !   314 _dispatch_client_callout  (in libdispatch.dylib) + 20  [0x1c035c1b4]
    +       !     314 _dispatch_call_block_and_release  (in libdispatch.dylib) + 32  [0x1c035a5f0]
    +       !       119 -[QSProcessMonitor _reloadProcesses]  (in QSCore) + 336  [0x10272e1fc]
    +       !       : 66 -[QSProcessMonitor infoForApp:]  (in QSCore) + 48  [0x10272d6c8]
    +       !       : | 66 -[NSRunningApplication processIdentifier]  (in AppKit) + 136  [0x1c3383720]
    +       !       : 45 -[QSProcessMonitor infoForApp:]  (in QSCore) + 128  [0x10272d718]
    +       !       : | 45 -[NSRunningApplication bundleIdentifier]  (in AppKit) + 108  [0x1c33a3700]
    +       !       : 3 -[QSProcessMonitor infoForApp:]  (in QSCore) + 56  [0x10272d6d0]
    +       !       : | 3 GetProcessForPID  (in HIServices) + 164  [0x1c61ebfa4]
    +       !       : 2 -[QSProcessMonitor infoForApp:]  (in QSCore) + 72  [0x10272d6e0]
    +       !       : | 2 -[NSRunningApplication localizedName]  (in AppKit) + 136  [0x1c33df248]
    +       !       : 1 -[QSProcessMonitor infoForApp:]  (in QSCore) + 156  [0x10272d734]
    +       !       : | 1 -[NSRunningApplication processIdentifier]  (in AppKit) + 136  [0x1c3383720]
    +       !       : 1 -[QSProcessMonitor infoForApp:]  (in QSCore) + 432  [0x10272d848]
    +       !       : | 1 +[NSDictionary dictionaryWithObjectsAndKeys:]  (in CoreFoundation) + 608  [0x1c05d7e60]
    +       !       : 1 -[QSProcessMonitor infoForApp:]  (in QSCore) + 448  [0x10272d858]
    +       !       :   1 _NSDictionaryI_mutableCopyWithZone  (in CoreFoundation) + 208  [0x1c05a3fec]
    +       !       104 -[QSProcessMonitor _reloadProcesses]  (in QSCore) + 320  [0x10272e1ec]
    +       !       : 98 -[QSProcessMonitor includeApp:]  (in QSCore) + 100  [0x10272d934]
    +       !       : | 98 -[NSRunningApplication bundleURL]  (in AppKit) + 108  [0x1c33a358c]
    +       !       : 3 -[QSProcessMonitor includeApp:]  (in QSCore) + 68  [0x10272d914]
    +       !       : | 3 -[NSUserDefaults(NSUserDefaults) boolForKey:]  (in Foundation) + 108  [0x1c1476b5c]
    +       !       : 2 -[QSProcessMonitor includeApp:]  (in QSCore) + 132  [0x10272d954]
    +       !       : | 1 -[NSString(NSPathUtilities) pathExtension]  (in Foundation) + 272  [0x1c1497478]
    +       !       : 1 -[QSProcessMonitor includeApp:]  (in QSCore) + 116  [0x10272d944]
    +       !       :   1 -[NSURL(NSURL) path]  (in Foundation) + 104  [0x1c1479b1c]
    +       !       71 -[QSProcessMonitor _reloadProcesses]  (in QSCore) + 360  [0x10272e214]
    +       !       : 67 -[QSProcessMonitor imbuedFileProcessForDict:]  (in QSCore) + 188  [0x10272d498]
    +       !       : | 64 +[QSObject(FileHandling) fileObjectWithPath:]  (in QSCore) + 248  [0x102715a64]
    +       !       : | + 61 -[QSObject(FileHandling) initWithArray:]  (in QSCore) + 468  [0x102714384]
    +       !       : | + ! 36 -[QSObject(FileHandling) getNameFromFiles]  (in QSCore) + 504  [0x102715248]
    +       !       : | + ! : 36 -[QSObject(FileHandling) fileUTI]  (in QSCore) + 16  [0x102714e90]
    +       !       : | + ! :   35 -[QSObject(FileHandling) infoRecord]  (in QSCore) + 68  [0x10271447c]
    +       !       : | + ! :   | 34 -[QSObject(FileHandling) loadInfoRecord]  (in QSCore) + 276  [0x1027145f4]
    +       !       : | + ! :   | + 34 -[NSURL resourceValuesForKeys:error:]  (in CoreFoundation) + 112  [0x1c05efa0c]
    +       !       : | + ! 19 -[QSObject(FileHandling) getNameFromFiles]  (in QSCore) + 396  [0x1027151dc]
    +       !       : | + ! : 19 -[NSURL getResourceValue:forKey:error:]  (in CoreFoundation) + 120  [0x1c05d5efc]
    +       !       11 -[QSProcessMonitor appTerminated:]  (in QSCore) + 28  [0x10272de0c]
    +       !       : 10 -[QSProcessMonitor processObjectWithPSN:fromSnapshot:]  (in QSCore) + 244  [0x10272d5ec]
    +       !       : | 10 -[__NSFrozenDictionaryM enumerateKeysAndObjectsWithOptions:usingBlock:]  (in CoreFoundation) + 192  [0x1c06253f8]
    +       !       : 1 -[QSProcessMonitor processObjectWithPSN:fromSnapshot:]  (in QSCore) + 68  [0x10272d53c]
    +       !       :   1 GetProcessPID  (in HIServices) + 140  [0x1c61ebe70]
    +       !       4 -[QSProcessMonitor appLaunched:]  (in QSCore) + 80  [0x10272dd58]
    +       !       : 4 -[QSProcessMonitor imbuedFileProcessForDict:]  (in QSCore) + 120  [0x10272d454]
    +       !       :   4 +[QSObject(FileHandling) fileObjectWithPath:]  (in QSCore) + 248  [0x102715a64]
    +       !       :     4 -[QSObject(FileHandling) initWithArray:]  (in QSCore) + 468  [0x102714384]
    +       !       :       3 -[QSObject(FileHandling) getNameFromFiles]  (in QSCore) + 504  [0x102715248]
    +       !       :       | 3 -[QSObject(FileHandling) fileUTI]  (in QSCore) + 16  [0x102714e90]
    +       !       :       |   3 -[QSObject(FileHandling) infoRecord]  (in QSCore) + 68  [0x10271447c]
    +       !       :       |     3 -[QSObject(FileHandling) loadInfoRecord]  (in QSCore) + 276  [0x1027145f4]
    +       !       :       |       3 -[NSURL resourceValuesForKeys:error:]  (in CoreFoundation) + 112  [0x1c05efa0c]
    +       !       3 -[QSProcessMonitor appLaunched:]  (in QSCore) + 28  [0x10272dd24]
    +       !       : 3 -[QSProcessMonitor infoForPSN:]  (in QSCore) + 36  [0x10272d9d0]
    +       !       :   3 ProcessInformationCopyDictionary  (in HIServices) + 280  [0x1c61eb510]

[pjrobertson]

Thanks mauritium. Thanks for the feedback – that's annoying that it's still an issue. I think there is a legitimate reason to not only include bundles in the processes list (e.g. if you are running a command line GUI app), but I do agree that those situations are more rare. Do you know what the actual processes are that are causing QS to rescan, and how many processes do you have running at any one time? I have ~120 .

[n8henrie]

@mauritium we're in a special situation since you have a dev environment set up!

Can you add something like the following (patch will surely be outdated) and let us know what your logs look like?

stash@{0}: WIP on main: 310597e9d Remove completed TODO

diff --git a/Quicksilver/Code-QuickStepCore/QSProcessMonitor.m b/Quicksilver/Code-QuickStepCore/QSProcessMonitor.m
index 07ea0d274..bcb6bfb14 100644
--- a/Quicksilver/Code-QuickStepCore/QSProcessMonitor.m
+++ b/Quicksilver/Code-QuickStepCore/QSProcessMonitor.m
@@ -296,6 +296,7 @@ OSStatus appTerminated(EventHandlerCallRef nextHandler, EventRef theEvent, void
 	
 	// if we're including background processes (i.e. all processes) OR if it's a foreground process, reload
 	if ([[NSUserDefaults standardUserDefaults] boolForKey:@"QSShowBackgroundProcesses"] || ![[dict objectForKey:@"LSBackgroundOnly"] boolValue]) {
+			NSLog(@"Will reload due to launching %@ from %@", dict[@"CFBundleName"], dict[@"BundlePath"]);
 		[self reloadProcesses];
 	}
 	if (dict) {
@@ -314,7 +315,7 @@ OSStatus appTerminated(EventHandlerCallRef nextHandler, EventRef theEvent, void
 	
 	if (processObject) {
 		NSDictionary *dict = [processObject objectForType:QSProcessType];
-		
+			NSLog(@"Will reload due to terminating %@ from %@", dict[@"CFBundleName"], dict[@"BundlePath"]);
 		[self reloadProcesses];
 		
 		QSGCDMainAsync(^{

[n8henrie]

A few other thoughts:

• this was part of my concerns about not having a reproducible test case!
  • can you confirm that my test script here reproduces the bug on your system?
• I still think that reverting the commit in question and instead implementing some kind of size 1 channel with a configurable timeout would resolve this issue with minimal user-facing changes
• @pjrobertson and I had a convo about this offline -- I would consider the changes to exclude XPC and background processes a user-facing breaking change; for example, it's hard to know how many users may be using QS to relaunch or force kill hung background or XPC processes.