Bug: Game File not Saved "Check Read Only" status

Having playing through the first (2) Contract Missions, after completing the 3rd Mission, the Game suddenly stopped performing "Auto Game Saves" and failed "Manual Saves". Like many others, because the Contract Missions can be a bit buggy about providing a "Completed" status, I was doing manual Saves with a Save Title of my choosing. This was simply so that I might not lose progress (during a Mission) if the Mission refused to give me credit for completing it (which they "can" do fairly often).

Side Note: I've since found that the "Missions" are very particular about the way you choose to complete the Tasks. We don't have the freedom to "get outside the box" in how we choose to accomplish Mission Tasks. Grind something, choose a different route of accomplishment, and you can find that you will have to "Abandon" and re-start the Mission.

Back to the game "claiming that is can't save the file". Just for grins, I decided (within the Game's menu choices) to Create a Copy of the last Game Save that I'd performed. I then re-loaded from that "Copy" and was again able to manually Save progress with no on-screen warning about "check to see if the save file is write-protected". It made me wonder if the Game has some limit to how many Manual, self-titled Saves that the Player can perform? At the time the problem started, I only had about 6 Manual Saves that I had titled (for reference).

Also, I am using no Mods, have not edited any Game files or otherwise done anything to trigger this problem and have plenty of Disk Space to perform Saves. I hope you can fix the problem in the Game and enable more people to stick with the "Alpha". When both the Game's Auto-save and my own Manual Save efforts were failing, I was ready to exit the Alpha and set is aside for a while.

All the best to you folks from a 10-year player of "Space Engineers".