See also Linux Annoyances for Terminal on Mac

Zoom Screen Sharing doesn't Work
Zoom: exclamation point in triangle - enabling screensharing permissions
If you try to share your screen, you may see a triangle with exclamation point in it. This is because MacOS Catalina added a new category of app permissions called “Screen Recordings”. This prevents a user from being able to share their screen through an app until permission is given specifically for that app. If you have NOT granted this permission, then if you try to share your screen through the Zoom app, there will be error images instead (showing an exclamation mark inside of a rectangle, instead of a preview of what you might be able to share)

To fix this:

  1. Settings
  2. Security & Privacy
  3. Privacy tab
  4. Screen Recording
  5. You may need to Unlock in lower-left of dialog (and provide password)
  6. Allow Zoom, or other apps you want to be allowed to use your screen
  7. Then lock
  8. You may need to restart Zoom.

Zoom Camera Doesn't Work

MacOS Catalina prevents the camera from being used until permission is given specifically for the app (such as the Zoom app). This is requested the first time you join a Zoom session:
“” would like to access the camera“
This is similar to the above (screen sharing). To fix this:

  1. Settings
  2. Security & Privacy
  3. Privacy tab
  4. Camera
  5. You may need to Unlock in lower-left of dialog (and provide password)
  6. Allow Zoom, or other apps you want to be allowed to use your camera
  7. Then lock
  8. You may need to restart Zoom.

Suppose you want all .xlsx files to open with LibreOffice instead of Numbers. Do the following.

  1. Find a file with the extension (.xlsx), right click, and Get Info.
  2. Under Open with, open the dropdown, find the application you want to open this type of file (LibreOffice), and select it.
  3. Click the Change All… button.
  4. Confirm that you want to make the change.

From this point on, all files with the same extension will open with this application.

If something goes wrong with printing, for example a bad file descriptors error, you need to reset the printing system. If you reset the printing system, you will

  • lose all print queues and pending print jobs
  • remove all printer preference files
  • removes all printers currently in the Printers & Scanners preference pane.

To Reset Printing System:

  1. Launch System Preferences
  2. Select Printers & Scanners
  3. In the Printers and Scanners preference pane, place your cursor in an empty area of the printer list sidebar (where the printers are listed) and right-click; select Reset Printing System from the popup.
  4. You're asked to confirm. Press Reset.
  5. You may need to enter administrator password or finger.

The printing system will be reset and you will need to add back your printer.

  1. Turn device on
  2. Press and hold the Cancel (X) button till green light blinks 5 times, then release
  3. Output is printed. On second page you'll find the IP address.

Leawo Blu-ray Player works.

  1. Mount the .iso (right-click on .iso file, )
  2. Run Leawo
  3. See: Open File and the DVD you've mounted
  4. Right-click on the DVD you want to play
  5. Play Disk

This is likely an alert that you have received new mail. To check and remove this:

  1. Open the Mail app
  2. Select Mail > Preferences
  3. General tab
  4. In the drop-down menu next to the New messages sound, select your favorite sound or None.

20190905 Have seen videos that playback super fast when there is audio in the file. Also happens when watching YouTube videos.
Problem solved by

  • Open Activity Monitor
  • Under CPU tab, find coreaudiod process, and click to select it.
  • Click the X-in-stopsign button upper left of the Activity Monitor screen, and Force Quit.
  • coreaudiod will restart and videos will play just fine.

20190923, happened again. Did the above, problem solved.

This from

  • Force Quit Applications window: Command+Option+Escape to summon the basic “Force Quit Applications” window (a simple task manager for OS X). Only shows windowed-applications.
  • Activity Monitor: Shows all applications in addition to windowed ones. Command+Spacebar type “Activity”. Select an app, use the X n upper left to bring up dialog allowing quit and force quit choices.
  • top: Run Terminal, command=top. Sort by cpu or memory usage: top -o cpu [or] top -0 rsize
  • ps: Run Terminal command=ps ps aux [or] ps aux | grep process

Property files are stored in /Library/Preferences. Run Terminal to work with. From

Following is example for Time Machine, limiting its disk use.

Time Machine by default will use all the available disk space on your backup drive. The good news is that you can setup a maximum limit that Time Machine can use. All you need to do is specify in megabytes the maximum space limit. You can do this by multiplying your Gigabyte preference by 1024 bytes. For example if I wanted the maximum backup space to be 100GB, I would multiply 100 by 1024 which equals 102400. I can then enter this terminal command:

sudo defaults write /Library/Preferences/ MaxSize 102400

This preference can be viewed within the /Library/Preferences/ file by

sudo defaults read /Library/Preferences/

To remove the limit, use the following command:

sudo defaults delete /Library/Preferences/ MaxSize

You want to delete files because the disk is full, but OS X won't let you do this because the disk is full.

  1. Reboot the Mac, and while it's rebooting press and hold Command-R
  2. When the MacOS Utilities window appears, select: Disk Utility and click Continue
  3. In Disk Utility, select the disk that's causing the issue, and use First Aid to look at and repair the disk.
  4. When this finishes, you can First Aid another disk.
  5. Then quit the disk utility and restart your Mac.
  6. Then empty the trash.

For example, you have lots of subdirectories in your Videos directory, and how can you determine which is using the most space?

  • Start Terminal
  • Change to the directory you want to look at (for example, cd Videos)
  • Enter the command du -hcd 1
    • du disk use
    • h human readable form
    • c show a total for the directory
    • d 1 depth, 1 means only top level, the subdirectories in the current directory

To use this and get a sort based on size: du -hcd 1 | sort -h (the -h on the sort reads first column as human readable values, that is it treats 800M < 1G as you would expect)

Digested from link

20191213 This did not work for me: I'd downloaded the Win10 ISO and followed instructions to create a boot USB stick.  The USB stick wouldn't boot. However I was able to use [[]] on a Windows machine to create a bootable USB stick.

You have an ISO file and you want to make a bootable USB stick from it. You will need a USB stick larger than the ISO file (e.g., ISO is 6GB, you can use a 8GB or larger USB drive. When done, the drive is completely full.)

  1. Run terminal
    diskutil list
  2. Find name of the USB stick (e.g., /dev/disk4; we'll use /dev/diskX here)
  3. diskutil unmount /dev/diskX

    or if that doesn't work do

    diskutil unmountDisk /dev/diskX

    you should see a message saying unmount was successful.

  4. Now go to finder and locate the ISO file. Right-click, and Copy <filename> as Pathname.
  5. Back to terminal, enter part of command (don't press enter yet)
    sudo dd bs=1m if=

    and then paste the pathname of the ISO file to the command and then add of=/dev/rdiskX

  6. For ISO file in smi's download directory with name silly.iso the command will look something like
    sudo dd bs=1m if=/Users/smi/Downloads/silly.iso of=/dev/rdiskX
  7. When it completes, type
    diskutil eject /dev/diskX

    see “ejected” message and unplug the USB stick.

bs is block size
if is input file
of is output file

Takes about 2 minutes to write a 6GB ISO file to a USB 3.1 drive.

20191213 I downloaded a Windows 10 ISO file from
You can find other Windows versions to download, see


  1. Open Finder window, navigate to your ISO file, single-click to select it
  2. File > Burn Disk Image
  3. Insert disk if you haven't already; click Burn

Alternatively you can right-click on the ISO file and Burn Disk Image

(For OS X 10.10 and earlier) From Umass link

  1. Applications > Utilities > Disk Utility
  2. Insert blank CD/DVD
  3. Drag the *.iso file from a Finder window to the Disk Utility window, drop in left pane in the empty area below the Mac drive names.
  4. Select the .iso file name in the left pane of Disk Utility, and click Burn (top left).
  5. The Burn Disk In: window opens and shows your CD/DVD as destination
  6. Click Burn
  7. When done the disk will eject

Suppose you're running Resolve and trying to archive a project, and maybe try to rename it. You can see that the Finder window for storing the project is the active window and it's also covered by the View Projects window, it's impossible to get to it. I figured out what to do on 20200105.

  1. Hold down Alt/Option key, move mouse to the Corner of the (Resolve main) window; see double arrow ←→ appear, double-click.
  2. Move the main window out of the way (to another monitor for example)
  3. For the monitor with the View Projects window is covering the Finder window, switch desktops away and then back.
  4. The Finder (hidden) window will appear; quickly drag this so it's outside the covering View Projects window.
  5. You can then work on the no-longer-hidden Finder window and continue.

To enter full screen mode:

  • Press green button in upper left
  • Control-⌘-F

To exit full screen mode:

  • Control-⌘-F
  • Move mouse to upper-left corner and let it sit. You'll see green button, press it.

To work in bigger window without going full screen

  • Press and hold Option key while click on the green button in upper left
    • Window expands, menu and dock remain visible
    • To exit, press and hold Option key and click on green button again
  • Or double-click on the app's title bar

exiting full screen mode in DaVinci Resolve isn't working – once I put Resolve in full-screen, I can't get it to exit full screen mode. [20200208]

Shift-⌘-4 Take screenshot of area on screen you identify

In terminal mode

defaults read current screen shot options
defaults write type jpgchange screenshot file type to jpg. Other options are: bmp pdf jpg tif pict tga png
defaults write name Georgechange from “Screen Shot 2020-07-02…” to “George 2020-0702…“
using “George 1” precedes with George 1 instead
defaults write location Users/smi/Pictures/Screenshotsstores there instead of desktop
defaults write “include-date” 0removes the date and time from the screenshot

and be sure to do this to load the settings (or reboot):
killall SystemUIServer

Monkey Bread Software. Has TreeSize and Show IP in menu bar.

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  • Last modified: 2020.10.09 20:53
  • by smismi7