SourceTree for Windows 1.6.12 won't install: "disk1.cab has an invalid digital signature"

Question

On my work computer, I'm not able to install SourceTree 1.6.12. It fails when registering components, saying "A file that is required cannot be installed because the cabinet file C:\Users\Granade\Downloads	emp\disk1.cab has an invalid digital signature. This may indicate that the cabinet file is corrupt."

I can install SourceTree 1.5.2 just fine, though.

I extracted the MSI and CAB files for both, and checked Properties > Digital Signatures > Details > View Certificate for both the 1.6.12 and 1.5.2 files. On the Certification Path tab for 1.5.2's disk1.cab, I get the following certification path:

thawte Primary Root CA
  ->Thawte Code Signing CA - G2
      ->Atlassian Pty Ltd

The last two certificates are OK, and the first is OK but not in my Trusted Root Certification Authorities store.

However, on the Certification Path tab for 1.6.12's disk1.cab, I get the following certification path:

Thawte Code Signing CA - G2
  ->Atlassian Pty Ltd

And the Thawte certificate is marked as "The issuer of this certificate could not be found."

Any idea why the difference? I'm guessing the missing issuer is what's causing the problem.

sgranade · Accepted Answer

Ha HA! I figured it out. For anyone else having problems installing SourceTree because of invalid digital signature, try installing the Thawte root certificates locally.

Head to https://www.thawte.com/roots/ and grab the root certificates zip file. Unzip the archive and open the "Thawte Primary Root CA - G1 (EV)" directory. Double-click the "thawte_Primary_Root_CA.cer" file to install the certificate.