Excel 2013 is very slow in loading large workbooks, is there a way to open just the tab I want?

Hi Jacques,

 

I found out a bit more about the reasons for the changes, and I can see why they were necessary. I also got permission to share some of the more technical details.

 

The changes were made to make us fully compliant with the ISO standards for DOX/DOCM open file formats. The capability was there in Excel 2010, too, but was implemented via policy. This causes us to go through the core Office files for protection hashes, and is in effect everywhere in Office, not just for worksheet and workbook protection. Also, in 2010 if you did implement the ISO hash protection, it would use SHA-1 hashes. In order to meet stricter security standards required by some of our customers, we moved to a default hash algorithm of SHA-1.

 

Regards,

Anita

Thanks for the insight.

Just a couple of clarifications,

you said "ISO standards for DOX/DOCM open" 

I'm guessing you meant "ISO standards for DOCX/DOCM open"

You said "it would use SHA-1 hashes. In order to meet stricter security standards required by some of our customers, we moved to a default hash algorithm of SHA-1."

I'm guessing that the second SHA-1 is supposed to be SHA512.

Hi Jacques,

I found out a bit more about the reasons for the changes, and I can see why they were necessary. I also got permission to share some of the more technical details.

The changes were made to make us fully compliant with the ISO standards for DOX/DOCM open file formats. The capability was there in Excel 2010, too, but was implemented via policy. This causes us to go through the core Office files for protection hashes, and is in effect everywhere in Office, not just for worksheet and workbook protection. Also, in 2010 if you did implement the ISO hash protection, it would use SHA-1 hashes. In order to meet stricter security standards required by some of our customers, we moved to a default hash algorithm of SHA-1.

Regards,

Anita

Thank you, Anita.

Hope this may have some results :)

Best regards

Jacques

Hi Jacque,

Have passed on everyone's comments to my program manager and sent a link to this thread.

Regards,

Anita

I see your point about the protection being stronger if someone uses Passware or another good protection removal. Have you tried it with Excel 2007? Can they really break the new hashes in a short time?

I tested with Excel 2013, because that's the version it's all about in this thread.

I didn't have to test with previous versions, because with Excel 2007 and Excel 2010 my workbook and worksheets programmatically protected during file opening, loaded (opened) immediately and there wasn't a problem with those versions. The slow loading appeared just with the new Excel 2013 due to the programmatic password protection during file opening. This was not the case with the previous versions of  Excel.

As I wrote, my password protected workbook containing 16 password protected worksheets was unprotected in a couple of seconds using Passware Kit 11.1 which I own. I started to use this software years ago because regularly I forgot my Excel passwords and hence I couldn't unprotect my worksheets anymore.

So I persist saying the reason quoted from the MS developers about the stronger protection method in Excel 2013 to keep my programmatically password protected workbook and worksheets loading much slower than in previous Excel versions is not very convincing, sorry to say that.

Best regards

Jacques