Open .vbox file and find following lines.
<Machine uuid="{xxxxxxxxxx-xxxx-xxxx-xxxxxxxx}" name="Windows7" OSType="Windows7_64" stateFile="{xxxxxxxxxx-xxxx-xxxx-xxxxxxxx}.sav" currentSnapshot="{xxxxxxxxxx-xxxx-xxxx-xxxxxxxx}" snapshotFolder="Snapshots" lastStateChange="2020-02-01T11:11:111">
and remove red part.
