If you use QuickSilver on the Mac, as an-application-launcher-and-more, you may discover that you are having performance problems. This seems to have been happening recently and occurs with the current release. Naturally, it all  depends on whether you ever look to see what resources are being used by your apps, but you will probably do that if you suffer from the QuickSilver issue I’m about to describe:

Primary Symptom: The Mac seems to be running slow. You may especially notice that some activities like downloads or moving between Spaces are slowed. Also some browser activities (FireFox or Safari) may cause the “spinning wheel” to appear.

Secondary Symptom: You run the Mac’s Activity Monitor and discover that QuickSilver is running at or above 90% of cpu. Note that no application should be that much of a hog, except in short bursts, but in this case QuickSilver is running at that level all the time.

Application Hoggery – A Note

In application terms, there are only a few resource hogs. Both Aperture and Photoshop can hog resources – but that’s normally because they’re busy doing useful stuff. Back-up utilities (like Time Machine) can hog the network (if they use the network) because they’re sending data to disk. Browsers do hog resources and can chalk up high cpu usage, and so, of course can Skype, especially when you use video. Virtual machines like Parallels chew up resources, but you should expect that. Apart from that the indexing routine that serves the Mac’s Spotlight Search capability is a nasty little resource hog – so much so that I disable it. (I never use SpotLight anyway.)

The QuickSilver Problem Described

When QuickSilver starts to tie up a cpu it is almost certainly because it indexing frantically and that’s causing it to “thrash”. Under normal running QuickSilver only uses a few percent of cpu. Here are four possible remedies, depending on the cause:

1. Cause: QuickSilver’s indexing files have got their “panties in a bunch” in some way. Quicksilver has become confused.
   Action: Quit Quicksilver. Go to ~/Library/Caches/Quicksilver/Indexes and move all the files out of there. (QuickSilver will recreate them.) Restart QuickSilver. If this doesn’t solve the problem try 2. below.
2. Cause: QuickSilver is frantically trying to manage its ClipBoard History. If you have set the number of clipboard items to remember above 25 items, this may be the cause – although it would need to be a high number to cause thrashing. Also check to see if you have the Shelf module as this can contribute to the problem.
   Action: Set ClipBoard History to 25 items. Switch Shelf module off. Quit Quicksilver and then relaunch. If this doesn’t solve the problem try 3. below.
3. Cause: QuickSilver is obsessively indexing its Catalog. This is most likely caused by Custom sources that you yourself have added.
   Action: Open the Catalog page in QuickSilver, and click on Custom. Go through the Sources you have added, one by one. For eacj click on i at bottom right corner of window and a draw showing source options will slide out. Click Source Options (bottom of the drawer) and it will shwo the depth of search. If you’ve set the search depth to infinity that’s almost certainly the cause of the problem. Set the value to no greater than the depth of the folder you want scanned (probably 3 at the most). Quit Quicksilver and then relaunch. If this doesn’t solve the problem try 3. below.
4. Cause: QuickSilver is indexing its Catalog insanely, but you never provoked it. This is most likely caused by a recent plug-in you added.
   Action: Open the Plugins page in QuickSilver. Start removing plug-ins you’ve added recently. (Best to take a snapshot of the ones you’ve got enabled first). You have to find the culprit, so the best way is probably to remove ones you know you added recently and while you’re at it, you may take the opportunity to remove ones you don’t use (if there are any). Quit Quicksilver and then relaunch. If this doesn’t cure the problem keep removing plugins.
   If you can’t make headway this way, then it may be a combination of a plugin and cause 1. above. In which case the only way out I can think of is to kill QuickSilver completely and reinstall. It performs fine on every installation I’ve done, so it should be clean on reinstall. After that add plug-ins one by one. Sorry but that’s the only way I know that can pin the problem down.

Incidentally QuickSilver is now Open Source and no longer controlled by its initial author. Problems caused by plugins are best directed to the plug-in authors, who will be best positioned to find out if the offending bug is in QuickSilver or the plugin.

Note: This posting also appears on the PDQ Mac web site, which is not officially launched yet. When it is launched, I’ll let you know.