However, I suspect that no-one who posts here can advise you how to avoid this, sorry. I am somewhat surprised if MS requires a continuous internet link. I realise it needs to check the validity of your licence but I thought this was just an initial check on first opening the program.
Exactly which version of Movie Studio do you have? Just as an experiment I opened MS2025 Suite, opened a project, began editing and then deliberately turned off my Ethernet (Internet) connection. No freeze or crash occurred. (Just for clarity, Wi-Fi is also turned permanently off for this desktop.)
So, I cannot replicate whatever is causing the problem for you; the "evidence" suggests it may not be the loss of internet.
I think you may need to create a Support Ticket to fully ascertain what is causing this for you. Click on the Support header in any forum page, follow carefully through each page you see, always choosing the option to Ask Support or Email Support (often at the foot of a page). Clearly, you are unlikely to receive any response until the New Year, unfortunately.
After a good and correct answer from Jeff, I have another question. Are you working from Microft OneDrive? If so, this is probably your problem. Close it.
It is best to work from your internal hard drives.
Thanks for the answers, I have uninstalled MS onedrive. It just reinstalls itself! I think it is an integral part the the spyware that is windows. I never have actually used it though. The problem is now unreplicatable for me as well now that I exchanged the old malfunctioning modem for a new one. Not necessarily fixed issue, but fixed cause... So...
I too could not replicate this behaviour but one thought occurred to me. If the program had not long been installed then it is possible the shop content was not fully downloaded and with a wonky internet connection could be a possible cause if the program was trying to download that while you were trying to work on a project. In the past I think that was a problem for some people but normally ended up with the program freezing.
What version of Windows are you on? One Drive on Win 10 Enterprise or Professional can be uninstalled. I have no idea about home editions.
. . . . I too could not replicate this behaviour . . . .
To replicate the issue you need to be logged into your PC using a Microsoft Account, with One Drive is set as the default location for you Documents files, ie they are uploaded direct to and used from OneDrive.
I don't log into a Microsoft account. When I first rebuilt my machine One Drive was loaded but it was one of the first programs I deleted. One also has to be careful of updates as Edge can also be a pain and been reinitialised more than once. Unfortunately that can't be uninstalled, only crippled, and I'm not convinced that can be done completely.
This too can be removed (Revo) however, do not remove the Edge Webview2 Runtime, doing so will cause issues with any installed program that requires this to connect to the Internet, this includes Magix programs.