I was using a 1 GB USB flash stick to back up my document files. No more files would copy even though the flash stick had only 2.4 MB on it (less than 1% full). Why?

What filesystsem is it formatted as?
What OS you using?
Whats the exact error given

File system is FAT
OS is Vista on one computer and XP on another
Error:
An unexpected error is preventing the operation. Make a note of this error code, which might be useful if you get additional help to resolve this problem.
Error: 0x80070052 The directory or file cannot be created.

This happens no matter which PC I am using to copy the files.

formate the drive and than try it.
dn't try to formate it by your pc .use it in other pc .

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