The lower thread is tangled. Upper thread is correct but lower is like along tangled threads. Sometimes it brakes needle. I checked bobbin case many times but it does anyway.

If your Babylock EMP6 embroidery machine starts stitching a design and then stops, displaying a message to check the upper or bobbin thread, there are a few potential causes for this issue:

1. Thread tension: Improper thread tension can cause stitching issues. Ensure that both the upper and bobbin threads are properly threaded and the tension settings are adjusted correctly. Check the machine's manual for specific instructions on setting the thread tension.
2. Thread breakage: Check both the upper and bobbin threads for any signs of breakage or tangles. A broken or tangled thread can cause the machine to stop and display the error message. If you find any issues, rethread the machine and ensure the threads are properly seated in the tension discs and bobbin case.
3. Bobbin issues: Check the bobbin area for any obstructions, such as lint or tangled thread. Clean the bobbin case and ensure the bobbin is correctly inserted and spinning freely. If the bobbin is wound unevenly or has any defects, replace it with a new one.
4. Needle issues: A bent or dull needle can cause stitching problems. Check the needle for any damage and replace it if necessary. Make sure you are using the correct needle size and type for the fabric and design you are stitching.
5. Machine maintenance: Regular cleaning and maintenance are important for the smooth operation of the machine. Clean out any lint or debris from the bobbin area, needle plate, and thread path. Lubricate the machine as recommended in the manual.

1. Needle: The needle may not be installed correctly, or it may be damaged. A bent or dull needle can cause thread tangling and result in the beginning of the top thread getting sewn into the bottom stitches.
2. Threading: The threading could be incorrect, or the thread tension may be too tight or too loose. Check the threading and make sure it's correct, and adjust the tension as needed.
3. Bobbin: The bobbin may not be inserted correctly, or the bobbin case may not be installed properly. Make sure the bobbin is inserted correctly and the bobbin case is properly installed.
4. Needle Plate: The needle plate may be damaged or not properly aligned. Check the needle plate and make sure it's not damaged and that it's properly aligned.
5. Upper threading tension: The tension in the upper threading may be too tight or too loose. Adjust the upper threading tension as needed.

1. Check the threading: Ensure that the upper thread is threaded correctly through the tension and take-up lever, and that the bobbin is inserted correctly in the bobbin case.
2. Adjust the tension: Check the tension on the upper and lower threads. If the tension is too loose or too tight, adjust it according to the instructions in your sewing machine manual.
3. Clean the feed dogs: Make sure that the feed dogs are clean and free of debris. If they are dirty, clean them with a soft brush.
4. Check the needle: Ensure that the needle is inserted correctly and is the correct size and type for the thread and fabric you're using.
5. Inspect the bobbin case: Make sure that the bobbin case is clean and free of debris. If it's dirty, clean it with a soft brush.

Do you have some pictures of the area involved. I know how to put these things back but I can't think how to explain it to you.. pics might help me show you.

Brother has an outstanding service department, and if you don't have a manual, they should have one. Should have a pic of how it goes together.

Unthread the machine fully. Remove the bobbin. Is the bobbin thread the same as the top thread? Is it a Quality thread (yes, cheapie thread can give big issues!!) Do you have several different threads wound onto the bobbin?? Is the bobbin thread wound on quite tight? If you push your finger nail into the thread wound onto the bobbin, it must not feel soft or spongy. Check if there is any roughness / burr on the any part of the shuttle hook. If so, remove it with 800 grade wet and dry abrasive or similar. Put in a NEW needle as per user manual specs (not a 'new' one you used before 'just for a little bit'.!) REPEAT - put in a NEW needle - amuse me!!. Place the bobbin into the bobbin holder (the CORRECT direction - yes there is a Right and a Wrong direction!), thread it ready to put back into the machine. BEFORE you do, hold onto the thread tail and let the bobbin and bobbin case dangle. Thread should slip thru when you give a gentle pull upwards. If no slip, loosen the tension on the tension finger a LITTLE. If it slides down easy, tighten it a little. Fit the bobbin into the machine. Lift the presser foot (this releases the top thread tension discs) Check there are no bits of thread or fluff between the tension discs Rethread the top thread - check the thread path is 100% correct. Hold onto the end of the needle thread and draw up the bobbin thread. Hold both threads, start to sew - check the result. Tip : If you use a different color bobbin thread (same brand etc etc) it will help you to see more easily what is going on. You should be seeing some of the bobbin thread color on the top side of the sewing. If not, INCREASE top tension a little - retry.If there is a lot showing, decrease top tension. Good luck

The motor locked up because the thread is tangled. Remove the tangled thread before continuing the operation.Clean the bobbin case to remove the tangled thread. After cleaning the bobbin case, insert the bobbin case properly. If the needle is bent or broken, replace the needle.Then, thread the upper thread properly, and continue the operation.
brother sewing machine

Upper thread breaks
1.needle may be in backwards
Correct needle insertion
Correct needle insertion is mandatory for proper use of sewing machine.
Raise the needle bar to the highest point, then loosen the clamp screw to remove the old needle, place the new needle in the clamp with the flat side to the back of the machine or if using a round needle--the groove in the needle should face away from the shaft.
Push the needle all the way up to the stop or as far as it will go, then tighten the needle clamp screw
2.upper tension may be to tight--try 3 to 5
3.the needle may be bent or damaged--try rolling the needle on a flat surface to see if it's bent or not
4.thread may be hanging up in bobbin case--check area for loose threads or lint
???
Lower thread breaks
The most probable cause of lower thread breaking is improperly wound bobbin
1.always start with a empty bobbin
Never wind one color over the other
2.choose thread that is identical in color & type as the one to be used for upper threading
3.wind the bobbin evenly across & in layers
4.don't wind the bobbin so full that it would be tight & hard to insert into bobbin case
5.bent bobbin--replace
6.lint built up in the bobbin case--frequent cleanings will eliminate this problem, the more often you use the sewing machine the more often it needs to be cleaned
7.thread catching on the bobbin spring or latch on bobbin case, check to see that the bobbin is inserted completely & correctly, & that you are using the right kind of bobbin

also check the thread take up lever to make sure the thread has not come off of it cause that can make the machine jam up also

Upper thread breaks
1.the needle may be bent or damaged--try rolling the needle on a flat surface to see if it's bent or not
Or the needle could be in backwards
Correct needle insertion
Correct needle insertion is mandatory for proper use of sewing machine.
Raise the needle bar to the highest point, then loosen the clamp screw to remove the old needle, place the new needle in the clamp with the flat side to the back of the machine or if using a round needle--the groove in the needle should face away from the shaft.
Push the needle all the way up to the stop or as far as it will go, then tighten the needle clamp screw
2.upper tension may be to tight--try 3 to 5
3.thread may be hanging up in bobbin case--check area for loose threads or lint
???
Lower thread breaks
The most probable cause of lower thread breaking is improperly wound bobbin
1.always start with a empty bobbin
Never wind one color over the other
2.choose thread that is identical in color & type as the one to be used for upper threading
3.wind the bobbin evenly across & in layers
4.don't wind the bobbin so full that it would be tight & hard to insert into bobbin case
5.bent bobbin--replace
6.lint built up in the bobbin case--frequent cleanings will eliminate this problem, the more often you use the sewing machine the more often it needs to be cleaned
7.thread catching on the bobbin spring or latch on bobbin case, check to see that the bobbin is inserted completely & correctly, & that you are using the right kind of bobbin

for the top & bobbin thread keep thread tails of 3 to 6 inches long pulled behind the needle before you start sewing

yes,sometimes the thread will get caught on the spool, you might think about getting a extra holder that sets behind the machine to hold those spool's that the thread get caught on, that's what I did.

have you checked the tension? In the older machines you could adjust the thread tension by tightening the screw on the side of the bobin case. With alot of the newer machines you have to lift out the bobbin and then lift out the casing to adjust the screw on the underside of the casing.

If the thread is hanging up at the spool - this could be the way it was manufactured, a nick in the spool end or the thread is unwinding too fast, puddling and wrapping around the spool pin.

Keep the bobbin case and surrounding area clean and free of thread tangles and snips. Thread tangles in this area can cause the machine to stop.

When the presser foot is down on any sewing machine, the tension closes and you cannot manually pull the thread through.

Sulky and C & C black tends to fray more than other brands of thread.

If the problem continues, the machine will need to be serviced by a professional.