You mean M$ Defender? If so how does that make sense? Every installation of MS Windows has it so surely the problem would be widespread... though maybe not if people don't allow Windows updates... I do though (does that make me weird!?! It would explain why so many machines aare easy to hack if everyone purposefully gimps their updates but I'm not convinced most people have that technical knowledge (however little that might be that is needed).)
I just checked the files again: Magisit 1.12 WIN/js/plugins/*
There is no VisuMZ_1_savecore.js but there is an AltSaveScreen.js and I wonder if there is a mistaken reference to the wrong file somewhere? I also wonder if I can find this file elsewhere since it looks to be a file common to the environment rather than yours?
Edit: Found a version from VisuStella MZ's Sample Game Project but it has a version mismatch, by fourteen days!! (So close!) - EditToo: No wait, that's my install date, note the version date, ack!
Edit Three: do you have a previous package of your game that might have the correct file?
Edit Four: Can I check something please? I have been searching for other games that contain this file and version 1.09 is too old but no version exists beyond that in the download of packages for games I can find... actually it exists but has been deleted by our virus checkers according to devs but at least one include a null .js file with the same name so it looks like it may be the _devs_ anti-virus that is deleting the file on packaging the build and then shipping a build without the file or with a truncated file... the only sources of the correct version of this file I have found are behind other games' paywalls where it has been posted for their own users.
Unfortunately it seems much more likely that the virus checkers of a few devs are at fault rather than the virus checkers of hundreds of users (from what I could tell of the number of complaints that this file was breaking builds), on top of this the real fault lies with the dev of the plugin, but I don't even know if they know this is happening... maybe you know who it is and can contact them or at least pass the message down the chain? If you pay for it you probably have more sway than us *shrug*
If I find a source for the file I will post it assuming it is legit and not illegal to do so (since it may breach the original devs conditions... who I presume is (as listed in the file itself) VisuStella MZ?? But if they are not the sellers then ?)
EditFive: Version 1.09 dates from Feb 2021 I think? So the new version dates from after that but we need a version from before Jan 2023 and it appears to update between months and years apart... the 1.09 version is still used in the VisuStella MZ Game Sample from Sep 2022 but then again another game is still using it in Aug 2023 so it seems that at least one dev might have found a solution (use an old version of the plugins!) but I couldn't find anything after Sep 2022 but before Jan 2023 that still exists.
Yeah, my AV quarantines files rather than deleting so I can tell it not to... also Micro$oft's form for submitting false positives (ie telling them their AV screwed up) is currently completely broken so without the dev trying to get in contact with them or hacking their file it won't get fixed... bad for everyone involved but M$, big surprise there *sigh* Monopolies get you bad software, big surprise.
Sometimes you can tell your AV to quaratine instead, or not to check certain directories... that could help but sometimes they also check at time of execution which means that they'll try and stop it when the file is run when you start the game and delete it then... at least this means you have a copy of the file you can copy back but it doesn't help running the game.