Disable video preview/quicklook in Finder
You can turn off the preview pane in Finder windows (column view) by going to Veiw: Show View Options (⌘+J) and unchecking Show Preview Column. This will disable video auto-play but I think your real issue is with a corrupted QuickLook or QuickTime preferences file. To find out if the root cause is as I surmise, create a folder on your desktop and move these files from /Library/Preferences (if you have them) into it
com.apple.quicklookconfig.plist
com.apple.QuickLookDaemon.plist
com.apple.quicktime.plugin.preferences.plist
com.apple.QuickTimePlayerX.LSSharedFileList.plist
com.apple.QuickTimePlayerX.SandboxedPersistentURLs.LSSharedFileList.plist

then restart &amp; see if the problem persists. Let us know the results please.