You could load the save in the editor, extract the contents and then in the save folder rename or move the lsv file. That may get rid of the error message, but it will do nothing for whatever changed in the file that triggered the error in the first place.
If this error happened after copying a save to another computer, try re-copying the save.
Do you have another recent working save? There is no way to determine if the change is something critical or minor or even observable, so if possible it would be better to be safe than sorry.
