Many Windows users have run into such a problem: connect external hard drive or USB flash drive to the computer and find that it’s not recognized. The accident can be caused by many reasons, for example, using the wrong file system, partition issues on your external drive, driver issues in Windows, dead USB ports, or some other unknown reasons. 9Apps Next we will show you how to fix all these external drive not recognized problems in Windows. Recover data from lost partitions due to re-partition, Cartoon HD boot manager, improper clone, system re-installation, disk accident etc. data recovery after system crash, hard drive error or failure, virus attack, unexpected power off, etc. Recover lost data due to accidental deletion, emptying recycle bin, and ‘shift+delete’ command without backups.