I have a Hoover Windtunnel and it works great. I get a huge bag tight full every other week or so (I live in a dusty place). Recently, the belt keeps falling off. It’s so bad now, it falls off immediately when the motor is turned on. Why? I really don’t want to buy another vacuum and I can’t do it now ($$) even if I did want to.
Should be able to buy a replacement belt…
The problem probably is in the main pulley. It must be lose and causing the belt to move off. Check your pulley and replace it if lose. It could be stripped.