foldersimacmacmacos
When I checked my Mac's harddrive I noticed that it was almost completely filled with files in the category 'other'. I used mac cleaning software to see what files were taking up a lot of space and those were mostly documents with names like: d8434hjk3hj5v3kj
Without any extension.
Will deleting these folders harm my mac?
Mac specifications:
– Mac OS X Lion 10.7.5 (11G63)
– 21.5-inch, medio 2011
I'm not much of a technology guy so if I need to be more specific please let me know.
HFS Plus (HFS+) is a fragile and a little outdated filesystem. If you google it, you'll find many reports of filesystem corruption.
Rebooting without unmounting the filesystem is the best way to corrupt it. This happens when the mac freezes for some reason (in my case it's the nvidia video card) or power failures.
Here are some tips, that IMHO should lower the chance of filesystem corruption:
When system freezes, try rebooting from ssh. When the graphics subsystem of my mac freeses, it's still accessible via SSH - try opening ssh connection from your network and reboot it. You could use Apple Remote Desktop (€62) for this task. You should enable ssh access first.
Do diskutil verifyVolume / periodically. Yes, even if HFS+ is a journaled filesystem, corruption is possible. You could use Apple Remote Desktop to run this on all classroom computers at once.
Use multiple volumes. Using multiple volumes should reduce chance for corruption. Splitting / from /Users/ should make restoration easier (either / or /Users will be corrupted). Note that this probably could complicate things with Bootcamp.
Mount partition(s) with options, which reduce writing. Mounting partitions with noatime option should reduce writing on it. By default every time a file is accessed, it's access timestamp is "touched".
Make sure there are no attempts to mount HFS+ partition from other os-es. Is it possible that someone is starting a linux distro from usb/dvd and mounting / in rw mode or playing with journal settings?
Hope my answer is helpful.
PS: corruption usually is gradual not sudden. There is a possibility that something specific is causing this, software or workflow. My mind is at Parallels 5, but it should corrupt the bootcamp volume, not the MacOS one. Searching their KB does not reveal anything useful.
PPS: it is fragile because it has no actual system to correct corruption within a file. A journal records transfers and attempts to recopy data in order to return the filesystem to a consistent state but if the file lost is vital (like actual filesystem structure data) then there is no recourse. In fact, because the Catalog File (which is lists all the logical data information) is stored as a file, if it corrupted in certain places your entire filesystem is rendered useless garbage data, or partially tended garbage in the event that it is corrupted and the a journal replay occurs which causes it to restructure the filesystem in a way that is not consistent with the data (e.g. file a and b are 1MB and 2MB respectively but the replay changes them to be 2MB and 1MB resulting in half of the contents of B being inside A).
The problem is that that your iMac is not waking from sleep.
Several people have been affected by this and discussed this on discussions.apple.com in these two threads. Both threads have been opened recently and deal with the "Wake on network access" problem in Lion.
It's required for your Mac to wake up because it needs to build up a Wi-Fi connection. Your iMac disconnects from the Wi-Fi in sleep mode. But without a connection to a known Wi-Fi network, Find my Mac cannot locate your computer.
This is what the iCloud troubleshooting guide says:
Find My Mac can only locate your Mac if it is connected to an internet via a known Wi-Fi network. If your Mac is connected to the internet only by an ethernet cable, Find My Mac will not be able to locate your Mac.
Does your iMac support wake on Airport network access? Newer Macs can wake up on both Airport and Ethernet access. This is then called "wake on network access" instead of "wake on ethernet/airport access".
If you iMac supports waking on Airport access, disable your Ethernet port. Maybe this will force the iMac to stay connected to the Wi-Fi during sleep and the 'bug' will not occur then.
Best Answer
I realize you might want a short answer, but in reality, the real question is have you set yourself up with a backup system that works well enough for you to go ahead and experiment and delete these files without serious repercussion.
My feeling is:
You shouldn't delete anything from /System or /Library unless you have a backup and have time and energy to perform a restore from that backup. No matter how good information you have, eventually your instructions, hunch, training or experience let you down and your machine won't work as you need it to.