At the risk of stating something obvious, I think there is a problem with the new software version.

The message is telling you that the software is unable to do something critical, not a comms issue IMO.

Have you asked the software vendor what it might all mean yet? How about uninstalling and reinstalling the new software?

How does the 'old' software save the data?

Well I contacted the vendor and he sent me a different link of software saying it is working on their PCs. I have tried to uninstall/install it several times and used different PCs but of no avail.

I concluded the same that this got to be a software issue but shared the question to see whether anybody else faced the similar problem or not. Thanks anyways.

Scan for malware or try the software with a clean install of windows. Malware is still written to intercept com ports for autodialer functions.

Also make sure all updates are installed. Run the software logged in as Administrator and see if the access violation goes away.

could you check the firmware numbers of the analysers? those are v1.68 or v1.74 or etc..?

v1.67

i hope it's not the case but with the MS servers years ago there was an issue like - i guess it was using the server's COM ports - the speciffic software had no privillegs to access them . . . ? however it managed to do some communication with the COM controller ??? the port parameters had to set manually ????????? & only xon/xoff worked . . . ????????? ??? ?
& another faint recall is the speciffic locking of sys res by the same (running) softw. or already uninstaleld / reinstalled 1 ????? "manual" removal of certain log or db files fixed the go <- it was with "our" software ?????