Mac Mini prohibitory symbol after defragmentation.

Question

Level 1

12 points

Mac Mini prohibitory symbol after defragmentation.

Hi again,

I recently used Drive Genius 3 to defrag my Early 2009 Mac Mini. After restarting it, halfway through the booting process, the prohibitory symbol shows up. I've tried resetting the NVRAM, repairing the disk with Drive Genius, and other attempts. After I defragmented the hard drive, I got an error message saying "disk0s1 was unmounted.". I've tried remounting the hard drive in recovery mode, but the Mount button is greyed out. When booting it in single user mode, I get a repeating code of "cannot mount root, errno = 19" with four other lines of code prior. May someone tell me what is wrong?

Thanks.

Specs:

2 GHz Intel Core 2 Duo

2 x 2 GB RAM Sticks

300 GB Hard Drive

OS X 10.11.4

Mac mini, OS X El Capitan (10.11.4)

Posted on Jun 6, 2017 7:10 AM

Reply

Answer 1

Klaus1

Level 9

52,879 points

Jun 6, 2017 4:22 PM in response to teeezeee

You will need to restore everything from your backup. You should never attempt to defray OS X:

Defragmentation in OS X:

http://support.apple.com/kb/HT1375 which states:

You probably won't need to optimize at all if you use Mac OS X. Here's why:

Hard disk capacity is generally much greater now than a few years ago. With more free space available, the file system doesn't need to fill up every "nook and cranny." Mac OS Extended formatting (HFS Plus) avoids reusing space from deleted files as much as possible, to avoid prematurely filling small areas of recently-freed space.
Mac OS X 10.2 and later includes delayed allocation for Mac OS X Extended-formatted volumes. This allows a number of small allocations to be combined into a single large allocation in one area of the disk.
Fragmentation was often caused by continually appending data to existing files, especially with resource forks. With faster hard drives and better caching, as well as the new application packaging format, many applications simply rewrite the entire file each time. Mac OS X 10.3 onwards can also automatically defragment such slow-growing files. This process is sometimes known as "Hot-File-Adaptive-Clustering."
Aggressive read-ahead and write-behind caching means that minor fragmentation has less effect on perceived system performance.

Reply