Upon launch Minecraft tries to write to the application folder. Of course, as per standard security practices, the application folder is not writable by normal users. Minecraft then displays the erroneous error message that it’s being run from a DMG volume.

See earlier reports that have been incorrectly closed

• MCL-8206
• MCL-11618
• MCL-4011 (Reopened)
• ….

This bug has been active for at least 2 years.

Correct behaviour is one of:

• Test for write access and don’t assume that the application can write to the application directory. Don’t do download if not writable.
• Test for write access and don’t assume that the application can write to the application directory. Request elevated privileges before trying to write to application directory. Only write if elevated privileges are granted.
• Use an appropriate writable directory NOT. THE APPLICATION DIRECTORY