Many folk will be surprised to find that your ability to recover USB contents using data recovery software diminishes if the drive/device is reaching full capacity. Here I’ll show you why this is the case and how you can reduce the chances of this problem occurring.
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How your data is stored and memory is reused
It is worth starting out by explaining how data is stored in the disk and therefore recoverable. Each document you save to your USB drive is stored as multiple data clusters located around the flash memory. An index or reference to these clusters is included in the file allocation table (a Windows system file included on hard drives and USB flash devices).
When a document is deleted/formatted it is only the file allocation table reference which is altered. The clusters still remain on the disk. This means you can recover formatted data and deleted documents simply by scanning the drive to identify clusters and consolidate them back into the files you once had.
Reaching full capacity
The problems start arising if you’re trying to recover USB files from a device that is almost completely full. Even though deletion/formatting of files does not remove the data clusters themselves, they are still marked available to reuse for the operating system (i.e. for storing new files).
As a result, as the USB drive is filling up your original lost/corrupted/formatted/deleted files will have their data clusters gradually overwritten with new documents. This process will increase as the disk is reaching full capacity since the device is running out of regular empty space to reuse.
Safeguarding against this occurring
The key to resolving this is always making sure that the USB device is not reaching 100% full capacity. Even leaving aside 10% left free at all times will help provide some available free space so that your original deleted/formatted data can be recovered at a later time.