Help: My Mac won't let me move or add files onto my hard drive


macrumors newbie
Original poster
Apr 14, 2011
I've got an iMac and a apple notebook and for either one, it won't let me add or move files onto it. It can let me take files out of it though. What's weird is it used to be able to but this just happened a couple of days ago, when I go to drag files onto it, it comes up with a circle with a slash sign.

Is there any way I can fix this problem without having to reboot my hard drive and erase everything? I might of just accidentally changed a setting but not that I know of.
Nov 28, 2010
Have you checked Finder > GET INFO >> Format and Sharing & Permissions yet?

Or are you talking about an external HDD?
If so, check the Format.
FAT32 (File Allocation Table)
  • Read/Write FAT32 from both native Windows and native Mac OS X.
  • Maximum file size: 4GB.
  • Maximum volume size: 2TB
NTFS (Windows NT File System)
  • Read/Write NTFS from native Windows.
  • Read only NTFS from native Mac OS X
  • To Read/Write/Format NTFS from Mac OS X: Install NTFS-3G for Mac OS X (free)
  • Some have reported problems using Tuxera (approx 33USD).
  • Native NTFS support can be enabled in Snow Leopard, but is not advisable, due to instability.
  • AirPort Extreme (802.11n) and Time Capsule do not support NTFS
  • Maximum file size: 16 TB
  • Maximum volume size: 256TB
HFS+ (Hierarchical File System, a.k.a. Mac OS Extended)
  • Read/Write HFS+ from native Mac OS X
  • Required for Time Machine or Carbon Copy Cloner backups of Mac internal hard drive.
  • To Read/Write HFS+ from Windows, Install MacDrive
  • To Read HFS+ (but not Write) from Windows, Install HFSExplorer
  • Maximum file size: 8EiB
  • Maximum volume size: 8EiB
exFAT (FAT64)
  • Supported in Mac OS X only in 10.6.5 or later.
  • exFAT partitions created with OS X 10.6.5 are inaccessible from Windows 7
  • Not all Windows versions support exFAT. See disadvantages.
  • exFAT (Extended File Allocation Table)
  • AirPort Extreme (802.11n) and Time Capsule do not support exFAT
  • Maximum file size: 16 EiB
  • Maximum volume size: 64 ZiB


macrumors newbie
Original poster
Apr 14, 2011
It's NTFS. Does that mean it only works with Windows? Because before it used to work with my mac.


macrumors newbie
Original poster
Apr 14, 2011
If I install that NTFS-3G for Mac OS X, will it erase my files? Sorry I'm really conscious of losing everything.


macrumors newbie
Oct 30, 2014
I followed this advice, now my Mac can't see the external drive at all

I've had this same problem, so I found this thread.

My Mac used to be able to both read AND write to my external hard drive with no problem, then it suddenly stopped being able to write to it.

I checked, and my external drive is Windows. So I followed the advice here and installed that software. Now my Mac can't even see the hard drive.

How do I fix this? If I uninstall this software, will it be able to at least see the hard drive again?

My internal hard drive is almost full. When I discovered I couldn't write to the external, I also found I could not copy files manually to a server either. I thought maybe the full internal drive might be the cause of the problem, but I can't seem to find any confirmation online.
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