If unable to unmount drive on macOS

You can try booting from OS X recovery by holding CMD + R at the time of startup. Once booted from OS X recovery, select Terminal from the utilities and then at the unix prompt enter:

  • diskutil list
  • then press return and look for the disk identifier and enter the following command with the disk identifier

sudo diskutil unmountDisk /dev/(enter here disk identifier name)

  • Press return and enter your admin password if prompted. This should unmount all volumes of the physical drive.
  • If still the above method didn’t work, then the last option is to force the entire disk to unmount.
  • For that using the terminal application again, enter the following command:

sudo diskutil unmount force /dev/(enter here disk identifier name)

  • Then press return and enter the admin password if prompted. This will definetely unmount the entire disk and all its related volume.

Clearing the quarantine extended attribute from downloaded applications – macOS

When I’m packaging an application for deployment, I normally download the latest version from the vendor. If it’s a drag-and-drop install, where the application is a self-contained bundle, it will get the com.apple.quarantine extended attribute associated with it.

The quarantine attribute is added by the OS so that it can ask for user confirmation the first time the downloaded program is run. Gatekeeper in Lion and Mountain Lion also uses the com.apple.quarantine attribute to determine if an application should be checked (and blocked if needed.)

To avoid issues with both unwanted messages and Gatekeeper, I normally clear this attribute as part of my packaging. Here’s how to check to see if your application has the com.apple.quarantine attribute associated with it:

1. Open Terminal
2. Run the following command:

xattr /path/to/MyApp.app

If the com.apple.quarantine attribute is associated with the application, you should see the following output:

xattr /path/to/MyApp.app
com.apple.quarantine

Note: Other attributes may also be listed, with com.apple.FinderInfo being a common one.
To remove the quarantine attribute, you would then run the following command:

sudo xattr -r -d com.apple.quarantine /path/to/MyApp.app

That will recursively remove the com.apple.quarantine attribute from the application. The -r option will allow the quarantine attribute of all files inside the application to be selected, while the -d option causes the given attribute name (and associated value) to be removed.

How to reinstall macOS from macOS Recovery

Learn how to use macOS Recovery to reinstall the Mac operating system on your built-in drive or an external drive.

macOS Recovery makes it easy to reinstall the Mac operating system, even if you need to erase your startup disk first. All you need is a connection to the Internet. If a wireless network is available, you can choose it from the Wi-Fi menu in the menu bar. This menu is also available in macOS Recovery.

Read moreHow to reinstall macOS from macOS Recovery

How to create a bootable installer for macOS

You can use an external drive or secondary volume as a startup disk from which to install the Mac operating system.

These advanced steps are primarily for system administrators and others who are familiar with the command line. You don’t need a bootable installer to install macOS, but it can be useful when you want to install macOS on multiple computers without downloading the installer each time.

Read moreHow to create a bootable installer for macOS

How to speed up Time Machine so it backs up your data faster – macOS

If you are a constant-on Time Machine user, you won’t even notice when a scheduled backup is taking place. That’s because Time Machine is designed to work quietly and slowly in the background. Most of your regular backups are incremental and therefore don’t need much power. If you only back up your Mac once per week (or longer), Time Machine has a lot more work to do, but still runs quietly and slowly in the background. Using this Terminal command, you will disable the disk operation throttling so Time Machine will run faster.

sudo sysctl debug.lowpri\_throttle_enabled=0

Restore default setup:

sudo sysctl debug.lowpri\_throttle_enabled=1

Which Synology NAS models does Migration Assistant support?

The below table lists Synology NAS models which are supported by Migration Assistant to work as either source or target server. The source server refers to the original Synology NAS from which data is moved, and the target server refers to the new Synology NAS.
Series Models
19-series RS1619xs+, RS1219+, DS2419+, DS1819+, DS1019+
18-series FS1018, RS3618xs, RS2818RP+, RS2418+/RS2418RP+, RS818+/RS818RP+, DS3018xs, DS1618+, DS918+, DS718+, DS418play, DS218+
17-series FS3017, FS2017, RS18017xs+, RS4017xs+, RS3617xs+, RS3617RPxs, RS3617xs, DS3167xs, DS1817+, DS1517+
16-series RS18016xs+, RS2416+/RS2416RP+, DS916+, DS716+II, DS716+, DS416play, DS216+II, DS216+
15-series RS815+/RS815RP+, RC18015xs+, DS3615xs, DS2415+, DS1815+, DS1515+, DS415+
14-series RS3614xs+, RS3614xs/RS3614RPxs, RS2414+/RS2414RP+, RS814+/RS814RP+
13-series RS10613xs+, RS3413xs+, DS2413+, DS1813+, DS1513+, DS713+
12-series RS3412xs/RS3412RPxs, RS2212+/RS2212RP+, RS812+/RS812RP+, DS3612xs, DS1812+, DS1512+, DS412+
11-series RS3411xs/RS3411RPxs, DS3611xs
The models in below table are also supported by Migration Assistant as either source or target server. However, please note that they cannot be used as target servers for the models mentioned in above table.
Series Models
17-series DS1817, DS1517
15-series DS2015xs, DS1515, DS715
Note:
Neither source nor target server can be VDSM or DDSM.
We recommend migrating to a Synology NAS with better hardware specification to ensure all packages and services will work properly after migration. Please visit Synology Download Center to find your product’s datasheet for more information.