Sometimes the trash won't be emptied, or a volume refuses to eject with a "file in use error." There have been hints on how to find that out in Terminal with lsof, which is not necessarily for the faint of heart.

Here is a nice Automator workflow that runs some AppleScript and shell commands and can be used in contextual Finder menu. So when a file is reported used, control-click on it and run the Automator workflow and see who is to blame. It will use user process space (no prompt for admin password), but will also revert to system process space if needed (prompting for the password). It will display the application/process that is using the file, and the account that started the program (could be you, could be root, could be another local user).

If you need to hold a print job for a period of time, but forget to change the settings in the Print dialog before sending the job to the printer, here's a solution.

When the printer's window comes up, click the Hold button, then double-click the value under "When. For the date, you'll need to enter the Unix epoch timestamp for when you would like the job to print. In case you're not fluent in UNIX epoch timestamps, you can use this free converter to convert a standard date format into the Unix epoch equivalent.

For example, if I wanted to print something at 2pm Eastern time on November 10 2009, I would enter 1257879600 into the field.

[robg adds: It seems this won't work in 10.6, because there's no When column in the 10.6 print queue window. If I'm overlooking something, please correct me and I'll remove the "10.5 only" tag from the hint.]

We have some users who, through habit or sloppy clicking, always shutdown their machine when they leave. This means that we can't perform maintenance without walking to the machine. If you need to prevent users from shutting down machines so you can do maintenance, this will help by removing the Shut Down item from the Apple Menu.

The following patch removes the Shut Down menu item for everyone on the system, admin and non-admin users alike. The patch doesn't delete the entire object, it just replaces the content of the object with a separator. Deleting the entire object causes Bad Things To Happen. You can probably use this method to remove other items in the Apple Menu, but I haven't tested that.

Warning: Altering anything under /System/Library is always risky. Don't deploy this without testing it thoroughly in your environment. I don't know for sure what will happen when updates are applied to the box, though I haven't seen any problems.

While people have pointed out that the CrashReporter dialog box may be disabled, this still runs the CrashReporter on each application failure, and writes a crash report to disk. Since it can take a long time to write the report, developers may want to disable crash reports entirely. Here is how.

From within a Terminal.app window, you have to run the following command once: You then have to run the following command every time you log in. (I added it to my ~/.bash_profile file, which is good enough for running tests.) Note that running defaults write com.apple.CrashReporter DialogType none definitely doesn't have the same effect as the above -- it disables the crash dialog, but Crash Reporter still contributes to the heat death of the universe.

If this hint works, you can thank Tim Shead of K3D fame. If not, feel free to clean up the broken pieces.

[robg adds: I haven't tested this one.]

Spotlight generally excludes OS X system folders (such as /etc and /bin) from its searches. But, if you know the name of the system folder you want to search, you can search in it anyway. For example, to search for a file in the /etc folder, select Go: Go to Folder in the Finder. Type /etc in the Go to field and click Go. With that folder now open in the Finder, type whatever it is you want to look for in the Finder window's Spotlight field. When the Search bar appears, select "etc" as the folder to search (instead of This Mac). If you select one of the found files and check its file path at the bottom of the search window, you'll see that the search results are indeed within one of those previously unsearchable folders.

Last year my wife and I returned from Thailand with some Bollywood movies we bought at a market. They aren't on DVD—some are on regular CD-ROMs (a mix of VCDs and regular CDs), complete with .avi files and .srt subtitle files, which we can play with VLC Player. However, I noticed that if the .avi and .srt files are in the same folder, and you press the space bar to preview the movie, Quick Look will show the subtitles in the movie. Previously I thought only VLC Player & QuickTime could do this. Quick Look even does this after I convert the .avi files to .m4v files.

[Editor's note: This hint has not been tested.]

According to this thread in Apple Discussions, some users are noticing some odd entries in Disk Utility's Repair Permissions function after running the Combined Updater and then repairing permissions. It seems a number of files are coming up with absolutely no permissions. Other users, though, are seeing no such problems. After a long exchange, user 'Gerben Wierda' seems to have figured out the cause and a solution.

Gerben describes the problem and the suggested solution:

For files not installed yet, their permissions (and owner) are taken from nonexisting files during the update process and stored in the package Receipts (Base system). Obviously, the combo update may affect more files. Installing the update twice -- without repairing permissions between -- re-reads permissions from the files which, at that point, are available and the receipts are fixed.

So basically, if you installed the combined updater and then repaired permissions, you need to install the combined updater twice, back to back, and then repair permissions will work properly. I haven't tested this, as (being very honest here) I only ever consider repairing permissions on my system if I've got an issue that seems like it might be related to permissions.

I have a portable drive that I've divided into two partitions: an HFS+ partition for backups and extra storage, and an MSDOS partition so that I can transfer large files or folders to or from Windows boxes. However, I don't need the second partition very often, so I wanted a way to keep it from automatically mounting on my machine when I plug in the drive, while still being able to access it quickly and easily. This turned out to be reasonably easy to do.

First, to prevent the partition from mounting when the disk as a whole mounts, edit/create the fstab system file, which lives down in the root folders at /etc/fstab. Leopard does not seem to have this file by default; it does have a file /etc/fstab.hd, which is not the file you want (though it makes for interesting reading in a Hitchhikers Guide to the Galaxy sort of way). Use a plain-text (i.e. programmer's) text editor such as TextWrangler, Smultron, or Editra, or use a unix tool like vi, and create a file called fstab with the following contents:

LABEL=PARTITION_NAME none msdos rw,noauto

Fields on this line are separated by tabs or spaces, so be careful to escape any spaces in your partition name. The escape character for a space seems to be \040 (octal 40) -- see the example in the man page for fstab.

After searching for a way to change the port that Apple Remote Desktop connects over (so I could use Screen Sharing to reach two machines behind the same NAT router), I found that in Screen Sharing, you can specify a port for a connection, just like you can do in Chicken of the VNC. So, to manage multiple computers:

1. Port forward a different port to your second, third, etc. machines. That is, port forward external port 5901 to internal port 5900.
2. Open the ScreenSharing app, in /System » Library » CoreServices.
3. Enter your Domain Name and Port: mydomain.com:5901, for instance, for the second port.

That's it -- off you go to the specified machine on the described port. I did have issues with Keychain remembering which username and password to use if you have different accounts on each box. I found that setting up domain aliases for each machine solved this -- i.e. server01.mydomain.com:5901, server02.mydomain.com:5902, etc.

Also, a great shortcut to remember is that you can simply type vnc://server01.mydomain.com:5901 into Safari, and it will launch the ScreenSharing app and connect. Likewise, you can bookmark these URLs (which I do to manage my computer list).

Want to read a bunch of related e-mails without switching to Mail.app? You can:

Start by using Spotlight to search for whatever subjects or recipients define the group of messages you want to read, then Show All the results. Next, click on the plus-sign (+) option. You should now see the search criteria Kind Is Any. Click and hold on Any and then choose Other. In the text field, type Mail Message. Now click on Save and give the search whatever name you wish; make sure that Add To Sidebar is checked. Select this saved search in your sidebar, and click on the Cover Flow button at the top of the Finder window.

You may have to enlarge your Finder window to make the messages readable. You could use QuickLook to read them at a larger size.