Sometimes you may find that your knitting yarn, apart from its inherent properties which can cause difficulties, appears to be faulty. Angora yarn for example is well known to shred a lot and for this reason angora is often combined with another yarn, such as wool, to strengthen it. Mohair is also known for being practically impossible to unpick.

However you may find something else going wrong. It may be that the yarn you are knitting with forms a spiral which renders a circular knitted item unusable (in which case try using it for flat knitting on two needles instead). In addition faults can be found which make it totally impossible to knit with a particular yarn. I have heard of two silk yarns which fell apart as they were being used, making them unusable. Many years ago my mother had problems with a very expensive pure wool yarn which had numerous knots in each ball.

I would strongly suggest that if you feel your yarn does have a fault like this (one knot in a ball is acceptable, more than that is not), you should write to the yarn manufacturer and let them know. It's even more important to do this if the fault materialises after the garment has been completed. An example would be my experience where I used two different colourways of the same make of 4 ply to make two separate sweaters. One sweater is almost like new, the other has pilled badly and though still very wearable and comfortable is no longer at its best.

It's often quite easy to find out if a particular yarn is giving problems. A quick search on any good search engine can reveal if there are web forum posts and blog articles indicating whether something you are experiencing is universally known to be an issue with this particular yarn. If it is, and the problem is something you can't cope with it's time to take the yarn back to the shop and write to the manufacturer. If it's a general issue but there is a solution (for example Noro Silk Garden is known to kink up badly but if you rewind the ball that helps to solve the issue) then it's a good idea to try the solution others have found helpful.

The main thing to think about if you have difficulties with any particular knitting yarn is to consider whether the problem can be solved and is worth spending your valuable time over. A yarn which falls apart before your eyes is not worth spending good knitting time on especially as a garment isn't likely to be very hard wearing if made in this material. If the balls or skeins of your yarn contain many knots and breaks this could also affect wearing quality. Remember, you want your knitted item to last a while once you have made it so that you can enjoy it (or the recipient for whom you are knitting can enjoy it). Something which pills so badly that holes form when the pills are removed, or sheds hairs all over the house, or falls apart beefore your eyes, is not going to do that. Move on and knit with something that works.

The reason you should let the manufacturer know if you have a serious problem with a knitting yarn is that they may have made a faulty batch. Most reputable manufacturers will in any case be very glad to have a helpful e-mail describing any issues their customers have had and will want to do something about the problem.