📎 AI Summary:
The user is concerned about binary differences between two identical-sized backup files, suspecting possible corruption due to previous copy errors. They inquire whether tools like CRC32 hashes, alternate data streams, or NTFS cluster checks can identify which file is valid or corrupted. A response indicates that, in this scenario, such methods won't be sufficient without a third reference copy to perform a definitive check.

pstein

Extraordinary Member
Joined
Mar 20, 2010
Messages
454
Thread Author #1
Assume I have a certain huge (> 2 GB) file and a second backup version of it on an external hard disk.

Both have exactly the same size and dates.

However when I compare them binary at the cmdprompt simplified with

fc /b D:\myfile123.enc H:\myfile123.enc

Then there are somewhere differences.
I guess these differences could be because of a previous errorneous copy operation in the past (or defect DVD).

Is there a way to find out which of them is corrupted and which is the valid file?

Is there e.g. somewhere a CRC32 hash code in the Alternate Date Stream?
Or in NTFS table?

Or can I check occupied NTFS clusters just for this file (not whole hard disk)?

Peter
 

ussnorway

Windows Forum Team
Staff member
Joined
May 22, 2012
Messages
4,598
In this senario no... if you had another (3rd) drive we could run a logic test.