I want to use SunDAT but that extension within SketchUp shows “Unsigned” and that is why I am not able to use it. Can you please suggest something to resolve this issue?
That just means the author hasn’t bothered to run the code through Trimble’s signing process. Contact the author and ask why.
In the mean time if you click the gear icon at upper right in the Extension Manager you can set your loading policy to unrestricted and then the lack of signature won’t prevent the extension from running. So long as you download from reliable sources such as the EW and SketchUcation or a known vendor’s site, there is little risk in unrestricted policy.