as far as I know, package is nothing but a zip file

so..

add ".zip" at the end of the package and Unzip it.

Good Luck To You

Thank you!
Yes, I know the trick, but opening the Xliff does not solve the problem because the package contains file settings, terminology, TMs, etc. Returning the package full of errors is not acceptable for them. Therefore I need to understand what happened with the update.

no 

I do not think you "know" it

I think there is nothing more I can do for you

Bye

There seems to be a problem with this update. See also https://community.sdl.com/product-groups/translationproductivity/f/studio/27412/error-processing-command-line-arguments/86989#86989 which includes a workaround for opening packages. I haven't updated to CU4 yet so I will test whether I run into this problem as well. Can you just confirm whether you are trying to open a project package from Worldserver or Studio? From what I can see (also from the Studio beta) the problem was for Worldserver project packages. The solution seems to be opening the package from Studio rather than double clicking the package: [File] > [Open Package] > select the package file.

Dear colleague,
I don't think you know what "I know"... I was perfectly aware of the trick you were suggesting, I have used it as a temporary solution, but it does not help me in solving the problem in the best way delivering the same package without errors (which is what I am trying to do).

Dear Daniel,

yes it is a Worldserver project package and your workaround worked perfectly, thank you very much! It really helped me, thank you.

Best regards,

Laura