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I am using MS Excel containing macro at customer place for some automation in excel. When the customer opens excel containing macro with the valid EV digital signature (Also tried with previously signed non EV code sign certificate) yet get the error “This digital signature is invalid and cannot be trusted. The macros will be disabled.” But when I checked my certificate, there is no error or problem found. And even the certificate exists in trusted publisher list of excel with matching thumbprint and expiry date. But still the error comes.

If I keep the excel file in trusted path (Or add current path as trusted path), it works fine. I cannot make the excel parent directory as trusted due to the reason that customer can keep the file anywhere in his PC.

I checked for the error in the multiple PCs, for all PCs having the OS higher than XP getting this error message and not able to run the macro irrespective of the office version. In XP error not found.

Is the trusted publisher no longer works in excel? What is the use of Trusted Publisher in MS excel?

How can I solve this issue?

Update:

I found the problem that it's the compatibility issue in the MS office for sha256.

Now as for my problem is it possible to sign the macro enabled excel with the sha1 algorithm using my sha256 EV code signing certificate?

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    As you have written, for all PCs having the OS higher than XP getting this error message,,, I guess the Macro has compatibility problem with higher version may be some library files are missing, Better you write the Vendor. – Rajesh S Jun 16 '18 at 11:08
  • I don't get how it's compatibility issue because macro works fine if i place or add current path as trusted path!. And one more thing i am the vendor here. – IT researcher Jun 18 '18 at 8:15
  • @RajeshS its indeed the compatibility problem but it's not the library. There is no compatibility for sha256 in MS office version 2007 and 2010 SP1. I still don't know how it worked in windows XP though. – IT researcher Jun 18 '18 at 11:57

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