Mac troubleshooting

Here are some tips for keeping your Mac in shape or fixing troubles.

General tips

Run Console, look for error messages there.

Run Activity Monitor, and sort by CPU usage by clicking the column header "%CPU". See whether any program is using much CPU unexpectedly.

Pay attention to sounds from the drives.

Don't use the battery if you can plug in where you are.

Specific issues

Going to sleep takes too much time

There might be something in the printer queue. You can check by pointing your browser to the CUPS queue: http://127.0.0.1:631/jobs/ or by looking in System Preferences>Print and Fax. Delete hung jobs.

Printing multiple copies takes too much time

CUPS, the printing system Mac OS uses to handle print jobs, has a feature that reads a variable called cupsManualCopies for each printer driver description, called a "pdd". When set to "true" and when the user asks for multiple copies of a document to be printed, the software renders the document that many times. So, if you are printing 20 copies of a two-page document, the Mac will generate and send 40 pages to the printer. When set to "false", the software is supposed to send just the two pages but with a command that tells the printer to make 20 copies. This would save much time, especially if you have a networked printer, and also prevent memory overload on the printer.

I tried copying the ppd for an HP LaserJet and changing its default "true" to "false", then creating a new printer instance with that altered ppd, but my Mac was still sending multiple copies itself. For my own situation, the fix was to use my printer's "copies" feature. I tell the Mac to send just one copy, but first I use the control panel on my LaserJet and set the number of copies desired.

See https://opensource.apple.com/source/cups/cups-327/cups/doc/help/spec-ppd.html#cupsManualCopies for a terse explanation of the feature.