Error: This file is not compatible with your actual version of Mathcad because it's from a newer version

[agiurca]

Good evening.

I cannot open my Mathcad files. The error message above appears. The files cannot be from a newer version of Mathcad as I have always used MathCad Prime 3.0. Any ideas how to solve this problem?

[agiurca]

I downloaded MathCad Prime 3.1 Express and it opens the files now. However this is VERY BAD because my student licence is only for MathCad Prime 3.0 and that version just got removed from my computer when I installed 3.1!!!

[RichardJ]

Well, you should expect that installing the later version of the software would remove the earlier version. Uninstall 3.1 and install 3.0 again.

You can't open a 3.1 file using 3.0, and 3.1 cannot save a file in 3.0 format. This is amazing, but true. So there is no solution. Sorry.

[VladimirN]

There is only one possible working out in this situation: before installing version Prime 3.1 copy the entire folder with the program Prime 3.0 version (for example on the desktop) and then after installing 3.1 you ca use it a 3.0 version too, but a worksheets conversion will only work for the 3.1 version

[RichardJ]

Thanks for the information. I'm surprised that works, because it must lead to a lot of invalid registry values. I guess Prime 3.0 and 3.1 are close enough that things don't completely break.

[Werner_E]

Luke Westbrook explained that method when he was asked if it would be possible that he provides a P3 worksheet instead of a P31 here

Easy Fit

which is the worksheet belonging to his blog post

http://www.ptc.com/Development/mathcad-software-blog/curve-fitting-made-easy

He created the P3 sheet by simply having both versions of Prime open and copying regions from the P31 sheet to a new P3 sheet.

I never tried it so I am not aware of any drawbacks other than not being able to convert older sheets to 3.0 format.

WE

[RichardJ]

I never tried it so I am not aware of any drawbacks other than not being able to convert older sheets to 3.0 format.

If it works as described, it also probably works to install 3.1, copy 3.1 to a new location, install 3.0. Then the converter will probably use 3.0. The new features introduced in 3.1 (i.e. the automation interface) probably won't work, but that's not necessarily a big deal. What may also work is to drop a copy of the 3.1 exe in the 3.0 folder, and run it by double clicking on it. If someone posts a copy of the 3.1 exe I'm willing to try it.