How do you repair flash drive which can't be formatted by Windows and other repairing tools?

1. How do I force a flash drive to format?
2. Which is better chkdsk R or F?
3. What is the command for chkdsk repair?

How do I force a flash drive to format?

Right-click the external drive or USB you intend to format and choose "Format". Set the Partition label, File system (NTFS/FAT32/EXT2/EXT3/EXT4/exFAT), and Cluster size, then click "OK". Click "OK" to continue. Click the "Execute Operation" button and click "Apply" to format the hard drive partition.

Which is better chkdsk R or F?

In disk terms, CHKDSK /R scans the entire disk surface, sector by sector, to make sure every sector can be read properly. As a result, a CHKDSK /R takes significantly longer than /F, since it's concerned with the entire surface of the disk, not just the parts involved in the Table of Contents.

What is the command for chkdsk repair?

To repair errors without scanning the disk for bad sectors, at the command prompt, type chkdsk volume: /f, and then press <Enter>. To repair errors, bad sectors, and readable information, at the command prompt, type chkdsk volume: /r, and then press <Enter>.