Your question is not only related to whether to upgrade to the latest version of CPC client, but also related to Office and its version. If you use WPS office or a higher version of Microsoft office, this problem is easy to happen and difficult to solve. I have encountered this problem before and it took a long time to solve it. However, I came across this article, "CPC client can't get system Office information when signing a contract (with a solution)". After following the instructions, I quickly solved the problem.

Finally signed successfully! I'm so happy.

The CPC client has been successfully signed.