Vacuum will not start in upright position. After vacuuming in normal position, we move the handle to upright position to use the hose vacuum and the vacuum stops. and will not start in upright position. If you let the vacuum sit for awhile then it will start, but only if you pull the handle back

SOURCE: No suction in upright position

Check the adapters at the bottom. They're supposed to move cleanly when you lower the handle. It's pretty obvious if there's an air gap when you lower the handle, and you should hear the suction in the air gap.

And...call Dyson...their support is great!

SOURCE: Vacuum lock

I just solved my own problem. I'm not much of a technical writer and I'm sure I don't know the proper terms but nonetheless...

...When standing behind the vacuum, as if using it, just above the right rear wheel is a detachable elbow for the air flow. The housing next to the wheel, wherein the elbow fits down into, is one segment of the problem the other segment, with which it may have come out of alignment, is the main front cover of the vacuum head. With the vacuum upside down in my lap I simply rolled the two components back into a position so that the front cover slides under the housing instead of bumping into it on top.

I hope this solves your problem too.

SOURCE: motor loud

when you put the handle down it turns on the brush roll. you may need to clean the brush roll or replce it if the bearings are bad.also clutch and 2 belts are started when putting handle down for brush operation.

SOURCE: beater bar on Dyson upright won't turn when handle is lowered

you need a new belt and maybe a new brushbar.

SOURCE: beater bar on Dyson upright won't turn when handle is lowered

I have finally fixed my sister's dyson dc 15 beater bar problem. It was just 2 tiny broken wires connect to circuit board lead to the beater bar. The wires broke where they go through the black rubber gommet. You need a torx screwdriver tx 15 to remove 2 plastic covers to access the wires. When looking at the front of the vacuum, the gray covers located on the right side of the vacuum. 1 big cover with a black rubber gasket and other small gray cover is on the rotating ball area.
This my new year resolution is to warn people not to buy Dyson vacuum cleaner ( Junk) design to break down! Shame on you Dyson!!!! Save your money find good old vacuum cleaner with metal parts.

OLD IS IN NEW IS JUNK!

Happy New Year!