I started fitting my TL100 today and noticed I am not getting the hold on it that I think I should. I've used several different tapes, but it just does not seem to get a good grip on the lace. Any suggestions as to what I could be doing wrong?

If it`s a brand-new system, give it a light shampooing, concentrating on the lace base.... it`s most likely factory-residue..they spray silicone/s on the hair before shipping and some can get onto the lace.... this can prevent proper adhesion..... ensure the lace is fully dry and try it again.

Did you use knot sealer? I've heard that it can sometimes cause tape not to stick well. You may need to shampoo only the base again and see if that helps as Paul mentioned above.

What tape are you using? It has been posted in many forums that people are having trouble with Supertape Low Profile. Some tapes have a harder time in grabbing these new thin laces. If you tried washing it and it still does not grab try a different tape. If you insist on using the same tape, apply the tape to the lace without peeling the back. Use a hair dryer and go over the tapes with high heat. Not to much, when the tape heats up go over the non peeled backing with your fingers, really pressing it to the lace. Then peel off the backing and apply as usual to your head.. I used to swear by Supertape low profile, but it just does not work with my new thin lace. I switched to walker no shine and all is back to normal.

I tried with Topstick and and unknown brand. However, I did not wash the unit first. I will try it again after I wash it.

I use stick it tape. Wow this stuff holds.

I also bought a SFS and I've tried 3 different tapes including the Walker No shine, and none sticks to the lace. I did wash with shampoo per the suggestions here, and it still not working. Any other suggestions are appreciated.

Put the first strip of tape on then overlap slightly with the second piece-this lets you use a finger nail to keep it in place while peeling off the backing strip.
Or try peeling the backing tape off then with a hairdryer on HOT, blast the tape for about 20 seconds. This should make the taped surface melt ever so slightly allowing it to grip to the lace.
The other option is stick the tape to your scalp first.
Regards