I like to routinely check my documents against backups by comparing MD5
signatures.
However, I find this impossible with Excel files because the MD5 value
changes just from opening and closing documents. I do not have this problem
with Word documents or any other type of file.
Could someone advise if there is an Excel setting that is causing this? If
so, do I need to use another file integrity checking method? What?

Anyone???

What is causing Excel documents to give different MD5 checksum values when
nothing is changed other than opening and closing the file??

"bogstick" wrote:

I like to routinely check my documents against backups by comparing MD5
signatures.
However, I find this impossible with Excel files because the MD5 value
changes just from opening and closing documents. I do not have this problem
with Word documents or any other type of file.
Could someone advise if there is an Excel setting that is causing this? If
so, do I need to use another file integrity checking method? What?

If you do a FC (windows file compare) between a copy of the file that
has been opened and one that hasn't, what is listed as different. (.xlsx
files don't change for me)

bogstick wrote:
Anyone???

What is causing Excel documents to give different MD5 checksum values when
nothing is changed other than opening and closing the file??

"bogstick" wrote:


I like to routinely check my documents against backups by comparing MD5
signatures.
However, I find this impossible with Excel files because the MD5 value
changes just from opening and closing documents. I do not have this problem
with Word documents or any other type of file.
Could someone advise if there is an Excel setting that is causing this? If
so, do I need to use another file integrity checking method? What?

You are right! This seems to be an issue only with Excel 2003 files!
When I used FC command, there was a small difference picked up!
I tried with 2007 .xlsx and the MD5 no longer changed!

So this is a fault of Excel 2003 documents? I wonder what the workaround
would be now if I were to still compare current Excel 2003 documents with
backup copies?

"Bob I" wrote:

If you do a FC (windows file compare) between a copy of the file that
has been opened and one that hasn't, what is listed as different. (.xlsx
files don't change for me)

bogstick wrote:
Anyone???

What is causing Excel documents to give different MD5 checksum values when
nothing is changed other than opening and closing the file??

"bogstick" wrote:


I like to routinely check my documents against backups by comparing MD5
signatures.
However, I find this impossible with Excel files because the MD5 value
changes just from opening and closing documents. I do not have this problem
with Word documents or any other type of file.
Could someone advise if there is an Excel setting that is causing this? If
so, do I need to use another file integrity checking method? What?

Ok, are you opening and closing the "Excel 2003" files with Excel 2007?
And if so, do they change every time you open and close them, or is it
just the first time.

bogstick wrote:

You are right! This seems to be an issue only with Excel 2003 files!
When I used FC command, there was a small difference picked up!
I tried with 2007 .xlsx and the MD5 no longer changed!

So this is a fault of Excel 2003 documents? I wonder what the workaround
would be now if I were to still compare current Excel 2003 documents with
backup copies?

"Bob I" wrote:


If you do a FC (windows file compare) between a copy of the file that
has been opened and one that hasn't, what is listed as different. (.xlsx
files don't change for me)

bogstick wrote:

Anyone???

What is causing Excel documents to give different MD5 checksum values when
nothing is changed other than opening and closing the file??

"bogstick" wrote:



I like to routinely check my documents against backups by comparing MD5
signatures.
However, I find this impossible with Excel files because the MD5 value
changes just from opening and closing documents. I do not have this problem
with Word documents or any other type of file.
Could someone advise if there is an Excel setting that is causing this? If
so, do I need to use another file integrity checking method? What?

Yes i am opening Excel 2003 files with Excel 2007.
And yes the MD5 signature changes each time the file is opened and closed!
Are you able to replicate this with a blank document?

"Bob I" wrote:

Ok, are you opening and closing the "Excel 2003" files with Excel 2007?
And if so, do they change every time you open and close them, or is it
just the first time.

bogstick wrote:

You are right! This seems to be an issue only with Excel 2003 files!
When I used FC command, there was a small difference picked up!
I tried with 2007 .xlsx and the MD5 no longer changed!

So this is a fault of Excel 2003 documents? I wonder what the workaround
would be now if I were to still compare current Excel 2003 documents with
backup copies?

"Bob I" wrote:


If you do a FC (windows file compare) between a copy of the file that
has been opened and one that hasn't, what is listed as different. (.xlsx
files don't change for me)

bogstick wrote:

Anyone???

What is causing Excel documents to give different MD5 checksum values when
nothing is changed other than opening and closing the file??

"bogstick" wrote:



I like to routinely check my documents against backups by comparing MD5
signatures.
However, I find this impossible with Excel files because the MD5 value
changes just from opening and closing documents. I do not have this problem
with Word documents or any other type of file.
Could someone advise if there is an Excel setting that is causing this? If
so, do I need to use another file integrity checking method? What?

What exactly are you trying to do?

--JP

On Sep 21, 11:16*am, bogstick
wrote:
I like to routinely check my documents against backups by comparing MD5
signatures.
However, I find this impossible with Excel files because the MD5 value
changes just from opening and closing documents. I do not have this problem
with Word documents or any other type of file.
Could someone advise if there is an Excel setting that is causing this? If
so, do I need to use another file integrity checking method? What?

I have some old backups of Excel 2003 documents and would like to verify
current copies against them! Therefore i am using the MD5 hashes for
comparing. But obviously this is failing because just opening and closing a
file causes the MD5 to change making the whole exercise useless! I do not
have any issues with any other type of Office 2003 documents.

"JP" wrote:

What exactly are you trying to do?

--JP

On Sep 21, 11:16 am, bogstick
wrote:
I like to routinely check my documents against backups by comparing MD5
signatures.
However, I find this impossible with Excel files because the MD5 value
changes just from opening and closing documents. I do not have this problem
with Word documents or any other type of file.
Could someone advise if there is an Excel setting that is causing this? If
so, do I need to use another file integrity checking method? What?

perhaps the modified date is not changed?

bogstick wrote:

I have some old backups of Excel 2003 documents and would like to verify
current copies against them! Therefore i am using the MD5 hashes for
comparing. But obviously this is failing because just opening and closing a
file causes the MD5 to change making the whole exercise useless! I do not
have any issues with any other type of Office 2003 documents.

"JP" wrote:


What exactly are you trying to do?

--JP

On Sep 21, 11:16 am, bogstick
wrote:

I like to routinely check my documents against backups by comparing MD5
signatures.
However, I find this impossible with Excel files because the MD5 value
changes just from opening and closing documents. I do not have this problem
with Word documents or any other type of file.
Could someone advise if there is an Excel setting that is causing this? If
so, do I need to use another file integrity checking method? What?

If the MD5 hashes aren't matching up, I would check the file size and
last modified date instead.

--JP

On Sep 24, 7:36*pm, bogstick
wrote:
I have some old backups of Excel 2003 documents and would like to verify
current copies against them! Therefore i am using the MD5 hashes for
comparing. But obviously this is failing because just opening and closing a
file causes the MD5 to change making the whole exercise useless! I do not
have any issues with any other type of Office 2003 documents.

No, the file size and modified dont change. I tried Excel 2003 files under
Excel 2003 and Excel 2007, and the issue affects both. How is it that FC is
picking up a difference yet the file size and last modified date remained
unchanged?

"JP" wrote:

If the MD5 hashes aren't matching up, I would check the file size and
last modified date instead.

--JP

On Sep 24, 7:36 pm, bogstick
wrote:
I have some old backups of Excel 2003 documents and would like to verify
current copies against them! Therefore i am using the MD5 hashes for
comparing. But obviously this is failing because just opening and closing a
file causes the MD5 to change making the whole exercise useless! I do not
have any issues with any other type of Office 2003 documents.

I don't know, but I think you should stick with my suggestion.

--JP

On Sep 26, 3:17*pm, bogstick
wrote:
No, the file size and modified dont change. I tried Excel 2003 files under
Excel 2003 and Excel 2007, and the issue affects both. How is it that FC is
picking up a difference yet the file size and last modified date remained
unchanged?

"JP" wrote:
If the MD5 hashes aren't matching up, I would check the file size and
last modified date instead.

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 and don'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-addin...nt-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/ex...010037593.aspx


Remove hidden data and personal information from Office documents. Excel 2013, Excel 2010:
http://office.microsoft.com/en-us/st...010354331.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.