Canister 1 canister not working

Should be under warranty. Take it to a warranty center for repair

Try here: https://www.amazon.com/Spares2go-Strong-Nilfisk-Cleaner-Fresheners/dp/B014DQDHX8/ref=sr_1_1?keywords=viking+canister+bags&qid=1565540526&s=gateway&sr=8-1

The canister has a filter as well. It needs to be replaced or cleaned. A damaged canister filter will feed dirt into the HEPA filter. (and the motor)
An improperly installed filter can allow dirt to bypass the canister filter and collect in the HEPA filter.
I suggest a new canister filter and then clean it carefully every week.
Here is a list of the filters for your vacuum.

I love the Dyson (DC07), but after 7 or 8 years it lost suction and needed some attention beyond filter cleaning. After much online research I found the few bits of advice that for me were the holy grail. After all of the standard stuff, clear clogs, clean filters etc..... In this order: 1) Remove & empty the canister, ***important****-leave the canister bottom lid open. 2) remove the three star screws at the top of the canister. It'll take a bit of pressure to pull the top up, there's a rubber seal. When you pull it up there will be a rod running down into the canister, leave it be, just pull up the top high enough to clear out any debris. 3) Put the top back on aligning the screws, when you lower it make sure the bottom of the rod engages with the hole at the bottom center of the canister, this is why you left the bottom lid open. Put the three star screws back in. 4) Turn the canister upside down, lid open, and keeping in mind this is thin plastic, gently tug upwards on the four fins that surround the bottom rubber seal. This part is held in by friction, so work your way around the four fins gently pulling until you work the ring they're connected to free. This will give you access to the inside of the canister. 5) remove the round perforated section by tugging upwards on it, set it aside with the fin part. 6) Take the canister to a laundry tub or large sink and holding it bottom up fill it with hot/warm water. Grasping the center section shake it vigorously and turn it upside down while shaking and a bunch of sh*t will come out. Repeat several times. 7) Dry thoroughly, you might use a hairdryer held to the center tube, but only if you can switch off the heat and use air only. Make sure its 200% dry, water will kill your machine 8) clean and replace the round perforated section 9) replace the fin section, I'd suggest pulling the round rubber part off of the fin part and setting it in place on the canister first, then follow with the plastic fin part. If you don't do it this way the rubber won't seat properly and the bottom lid won't close. 10) Close the lid, replace the canister, and staaaaaart suckin like it's brand new.

If the usual clog clearing and filter cleaning doesn;t work-> I love the Dyson (DC07), but after 7 or 8 years it lost suction and needed some attention beyond filter cleaning. After much online research I found the few bits of advice that for me were the holy grail. After all of the standard stuff, clear clogs, clean filters etc..... In this order: 1) Remove & empty the canister, ***important****-leave the canister bottom lid open. 2) remove the three star screws at the top of the canister. It'll take a bit of pressure to pull the top up, there's a rubber seal. When you pull it up there will be a rod running down into the canister, leave it be, just pull up the top high enough to clear out any debris. 3) Put the top back on aligning the screws, when you lower it make sure the bottom of the rod engages with the hole at the bottom center of the canister, this is why you left the bottom lid open. Put the three star screws back in. 4) Turn the canister upside down, lid open, and keeping in mind this is thin plastic, gently tug upwards on the four fins that surround the bottom rubber seal. This part is held in by friction, so work your way around the four fins gently pulling until you work the ring they're connected to free. This will give you access to the inside of the canister. 5) remove the round perforated section by tugging upwards on it, set it aside with the fin part. 6) Take the canister to a laundry tub or large sink and holding it bottom up fill it with hot/warm water. Grasping the center section shake it vigorously and turn it upside down while shaking and a bunch of sh*t will come out. Repeat several times. 7) Dry thoroughly, you might use a hairdryer held to the center tube, but only if you can switch off the heat and use air only. Make sure its 200% dry, water will kill your machine 8) clean and replace the round perforated section 9) replace the fin section, I'd suggest pulling the round rubber part off of the fin part and setting it in place on the canister first, then follow with the plastic fin part. If you don't do it this way the rubber won't seat properly and the bottom lid won't close. 10) Close the lid, replace the canister, and staaaaaart suckin like it's brand new.

I cut a strip of window screen about 1 inch wide and 12 inches long and slid it up the tube from the back of the vacuum. The screen edges grabbed the gunk and as I pulled the screen strip out from the tube the gunk came with it, clearing the blockage.

if its just a piece of foam it don't matter.if it has a cloth covered side the the cloth will be towards the outide of the canister

hi take off canister cover remove bag now if you look inside canister you will/should see a gauze type filter at the opposite end of canister from where bag locks in ?? remove this gauze filter and for now just shake tap on floor to remve dust/debri etc /from it this gauze is the filter that when vac is working andfilling the dust bag ? the pressure of air only that blows bag up but allows only air to pass thro the microscopic holes in bag ? then has to expel via the gauze filter to exterior ? and any dust etc that is clever enough to seep through the bag ??? will not pass further due to gauze ? and so prevents this blowing back into room ok so far ?? if this gauze is blocked due to whatever ?? then pressure build up in canister will result in cover lifting? this is provided that the fault is not the actual cover securing latch is ok and not damaged ? hope this explains and helps ? best wishes from uk !