Get rid of Mac overlapped extent allocation error

Mac OS X is a highly popular operating system having rich graphical interface and rich controls. In some cases, you may come across disk accessing problems with your Mac OS X.

Let us consider in a practical scenario, while using your MacBook Air you come across the following error message:

“Overlapped extent allocation”

On getting this error, disk checking process terminates. It will make all your precious data inaccessible. For resolving this error, it is necessary to find out the reason responsible for it.


Mac overlapped extent allocation error occurs due to overlapping of allocation space. When this error occurs it indicates that the two files are taking same disk space. In such situations, it is quite obvious that one of these files will be lost. Mac OS X reports this error when fsck or disk repair utilities fail to fix the errors. When such errors occur, you should not install new software having affected drive on your MacBook Air.

How to fix Mac overlapped extent allocation error:

In order to resolve this error you can perform ‘Erase and Install’ installation of Mac OS by using installation disk. However, you should always back up your critical data before going for it. Maintaining a backup is necessary in order to prevent your precious data from being lost. In the absence of a valid backup you can take the help of third-party Mac data Recovery tools to perform MacBook Air Data Recovery. These applications use advanced scanning techniques to deeply scan the entire hard drive and recover all your lost, corrupted, missing or inaccessible files.

Moreover, these applications have rich graphical user interface which allows you to perform data recovery from almost all data loss scenarios. It is compatible with Mac OS X 10.6 Snow Leopard, 10.5 Leopard, 10.4 Tiger, and 10.3.9 Panther. It allows you to recover lost data from HFS, HFS+, HFSX, HFS Wrapper, and FAT file system volumes.

System Requirements

Processor: Intel Power PC (G4 or later)

Operating System: OS X 10.6 Snow Leopard, 10.5 Leopard, 10.4 Tiger, and 10.3.9 Panther

Memory: 256 MB

Hard Disk: 40Mb