File integrity checking?

[Bogstick]

Great you confirmed the issue but i dont understand your theory.

If one file is a backup of the other, the the two should be exactly the same
for both Date Modified and File size. The only thing that has happened is
that i ve opened and closed the original file.
Are you saying Excel 2003 files include a count for how many times you view
it?

 

[JP]

No, I'm saying that you should stop polluting your goal statement (to
check backup files) with a solution (use MD5 hashes). You've
demonstrated that the MD5 hashes for Excel files aren't a reliable way
to compare files. If so, why continue to bother with them? Just use
the file size and/or last-modified date to verify that a file copy is
the most up-to-date backup.

--JP

 

[JP]

Agreed with you, if the filename and last-modified date are the same
for both, the files could safely be considered the same (for most
purposes). I'm sure others could also suggest additional criteria.

--JP

 

[Bob I]

No, I'm simply pointing out what changes and where. As to the solution
to your original problem. Recommend you check file size and modification
date as to determine "sameness". If you wish to continue with the MD5
check, convert the 2003 files to 2007.

 

[toravalenzuela]

I had the same problem, and after several hours reading through several forums and pages I found the root cause of the problem and solution, so I'll be copy&pasting my answer on the forums I read.

There seems to be an issue with excel files, in particular Excel 2003 xls files, whenever they get opened in Excel, even if they don't get changed anddon't get saved, Excel automatically updates some of the file's metadata, such as the "Document Properties and Personal Information" and "Last Accessed Statistics", therefore the file every time it gets opened changes a little bit, and this makes that the MD5 changes also.


To learn to view the advanced properties for an excel file:
http://www.ablebits.com/office-addins-blog/2014/01/22/excel-document-properties/


Solution:


One way to avoid this problem is to remove "document properties and personal information".


Remove hidden data and personal information from Office documents. Excel 2007:
http://office.microsoft.com/en-us/e...mation-from-office-documents-HA010037593.aspx


Remove hidden data and personal information from Office documents. Excel 2013, Excel 2010:
http://office.microsoft.com/en-us/s...tion-by-inspecting-workbooks-HA010354331.aspx

Other way to avoid this would be to use xlsx files. I have been trying to replicate this behavior in xlsx files, but it seems it only happens on xls (2003).

Regards,

Caridad J. Valenzuela R.