Yes, I looked in the mmc to export it after I installed it, and the type said code signing
SignTool Error: This file format cannot be signed because it is not recognized
Nerd With Coffee
0
Reputation points
I have been attempting to sign a .cat file, but I keep getting the error message that the file format is not recognized. I thought that maybe it was the file itself, so I tried with .pdf, .txt, and .exe files, but the same thing happens. I have a valid certificate, timestamp url, and I even tried to set the path of the signtool.exe as well as the file I'm attempting to sign into the path with set path=%path%;C:\Document\Here. I still get the message. My SDK is updated to the latest build and I don't currently have any windows updates for my x64 bit Windows 10 MSI laptop. I also have the command prompt in admin mode, and the line I am using is signtool sign /a /tr http://timestamp.digicert.com /td sha256 /fd sha256 /v "C:\File\Path\Here" . I even have my cd path set to where my signtool.exe is located: D:\Important Stuff\bin\10.0.26100.0\x64>
I'm not sure what else I can do as I've been researching this for a good amount of time now and I've started hitting dead-ends or already attempted solutions
Windows development | Windows App SDK
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Darran Rowe 2,171 Reputation points2025-08-04T02:53:01.5+00:00 I don't have any issues signing an executable with signtool. The only thing that I will ask, are you sure that the certificate is a code signing certificate?
It will not work otherwise.
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Nerd With Coffee 0 Reputation points
2025-08-04T03:17:38.24+00:00 -
Nerd With Coffee 0 Reputation points
2025-08-04T03:18:11.3733333+00:00 -
Nerd With Coffee 0 Reputation points
2025-08-04T03:24:22.4266667+00:00 Here's the screenshot. I forgot to just copy and paste it so it's easier
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Darran Rowe 2,171 Reputation points
2025-08-06T17:42:58.8433333+00:00 Did you export the private key along with the certificate? If you use the /sha1 command line option to reference the certificate installed on the system, does it work?
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Nerd With Coffee 0 Reputation points
2025-08-07T01:29:30.5733333+00:00 Yes, I had the key exported with the certificate. And when I use the /sha1 command, it says it completed successfully. That's more than I've gotten before with this file though
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Darran Rowe 2,171 Reputation points
2025-08-07T13:33:58.8+00:00 What is the format of the certificate? Is it .pfx? Is it something else?
If it isn't .pfx, how are you connecting the certificate with the private key?
If it is .pfx, does it contain the complete certificate chain? What happens if the /sha1 option is used to explicitly identify the certificate you wish to sign with?
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Nerd With Coffee 0 Reputation points
2025-08-07T17:52:14.22+00:00 It's a .pfx file, and when I input signtool sign /a /tr http://timestampdigicert.com /td sha256 /fd sha256 /f "D:\Important Stuff\Tools\certificates\certificate.pfx" /p key "path\to.cat\file", it still says SignTool Error: This file format cannot be signed because it is not recognized.
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Nerd With Coffee 0 Reputation points
2025-08-07T18:00:39.65+00:00 But, using the /sha1 command, I get SignTool Error: No certificates were found that met all the given criteria. I'm not sure if this is due to the certificate and signtool being in a separate drive than the file I'm trying to sign though
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Darran Rowe 2,171 Reputation points
2025-08-08T20:32:44.8766667+00:00 The location of the file that you are trying to sign in regards to sign tool and the certificate is irrelevant.
As long as the full paths are provided and the file that is being signed is writable then signtool doesn't care.
I also generated a .cat file and used signtool to sign that, and it just worked.
So what format is the .cat file? Is it the default,
PKCS_7_ASN_ENCODING | X509_ASN_ENCODINGwhich could be represented as0x00010001or is it some other format. -
Nerd With Coffee 0 Reputation points
2025-08-08T20:39:41.09+00:00 The only thing it tells me is that it's a security catalog .cat file. The properties don't tell me anything else
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