I have Brother Dreamweaverxe vm6200d sewing machine. It has been working just fine but the other day the upper thread began wrapping around the bobbin. What can I do to fix the problem?

SOURCE: Upper thread wraps around bobbin mechanism, while sewing

IT PROBABLY IS THREADED INCORRECTLY. GO SLOWLY BY THE DIAPHRAGM AND MAKE SURE IT IS THREADED CORRECTLY. ALSO MAKE SURE SPOOL PIN HOLDERS ARE IN PLACE THAT HELPS TO GUIDE THE THREAD CORRECTLY.

SOURCE: Not picking up the Bobbin thread

I cleaned the machine good with canned air, oiled it. I took out the bobbin case and cleaned it good also. I then noticed the tension screw on the bobbin case was loose, tightened it and the problem was fixed.

SOURCE: Brother sewing machine cs6000i. Less

check you tension on the top thread and see if you have it threaded the right way. Also see if the indent of your needle "the indent down by the hole on the needle" is facing the hook by your bobbin case that grabs the thread when it comes around.
Greg

SOURCE: My Disney Brother SE-27OD Embroidery Sewing Machine/trouble

Can you buy embroider memory cards with out down loading on your PC?

SOURCE: Upper thread knots up with bobbin thread when sewing a stich

Thread test
Test your thread quality to start, thread your machine and LIFT the presser foot (this opens the tension disks). Pull your top thread straight back. If you feel no tension no mater how much thread you pull, your thread is good. If that your machine passes that test, then let me know, we can go to step 2. If not, try different spool of thread, same test until you get a smooth pull (tip: always check your thread this way when you thread your machine)
Step 2:
Pull on your threaded bobbin thread while it’s in the machine. Does it pull smooth and even? If so, go to step 3. If not, try a new bobbin (bobbins get bent or distorted if wound too tight).
Clean thoroughly in the hook and bobbin case area and oil 1-2 drop is all.
Thread knotting on the bobbin can be a lot of things but here's some guidance:
Tension:
If the thread is loose on the bottom of the fabric, it's actually the top thread is too loose. Think of 2 little elves playing tug of war in your machine, one on toip and one underneath. If you have loops on bottom, the top needs to pull harder (tighten top tension)
Jamming bobbin case:
If it is damaged from turning out of place once, it could have rough spots on it that makes the thread hang on it, and keeps making it turn over and over. Use a finger nail board (fine sanding) and smoothall rough spots. Then reset the bobbin case taking care to put the notch in the bobbin case in alignment with the proper spot in the machine (basically 5 o’clock) when looking at the round area where the bobbin case goes.