SanDisk Cruzer 16GB U3 keeps showing a Format message
 

SanDisk Cruzer 16GB U3 is my first USB pen drive for my first laptop. It has been working fine for some time. Today I have copied some photos from the Nikon S8000 camera. The transfer was successful but after that whenever I try to use the drive, the system shows me a format message saying that the disk is not formatted, Do you want to format it now?...What kind of problem is this?

re: SanDisk Cruzer 16GB U3 keeps showing a Format message
 

As far as I know that only 2 things can cause this problem. The first problem is, the FAT is corrupt and for that you have to format the drive to fix it. The second thing is, the drive itself is bad or faulty. If you cannot format the drive, the obviously the drive is broken or bricked.

re: SanDisk Cruzer 16GB U3 keeps showing a Format message
 

I just bought a 16 GB Cruzer Micro from Sandisk and I had the same problem. I formatted to FAT 32 but despite that I could not copy a file on it. I found the solution, I said that I am running Windows XP, in fact FAT 32 does not work for files 4GB +. In desktop right click on removable disk / Properties / Hardware tab. Then select "Sandisk Cruzer USB" and click properties. Go to the Policy tab and select "Optimize for performance" and then OK to validate. Then it will format the key as NTFS. Right click on removable disk in My Computer and then format, select File System as NTFS then Start, and then after it works nickel.

Re: SanDisk Cruzer 16GB U3 keeps showing a Format message
 

For those who have a problem with FAT 32, you should know that you cannot copy files larger than 4GB, to remedy this, it is necessary to switch your support to NTFS, it is not necessary to format, just convert it using the following command:
Convert the <lectre drive> / fs: ntfs
Careful with spaces.

Re: SanDisk Cruzer 16GB U3 keeps showing a Format message
 

It seems to me that you have stored more than 4GB on Fat32 formatted flash drive and due to this the system is keep asking for you to format the drive into a different format like NTFS or Exfat. AS far as I know that the flash drive which is converted to Fat 32 can take up to only 4GB of data. So if you have stored or going to store more than 4GB on this drive, then you have to change it NTFS format.