Based on your image, It seems that your vector is not properly digested. You may do sequential digestion. Please also check your enzymes for their desired activity by simultaneously digesting another DNA or plasmid having ClaI or SalI restriction sites. Have you also digested this vector with another enzyme(s)?

Hi

The image depicts that the vector has not been digested completely. You must ensure that enzymes used by you are working efficiently. If you have doubts with your plasmid dna then you can cross check it with either in PCR (amplify cp specific primers) or try to digest with other enzymes of MCs region. If your plasmid is okay, then you need to reconsider your restriction enzymes.

Good luck!

This looks to me an undigested intact plasmid. Which you are mentioning as multiple fragments they are basically different confirmations of same plasmid. If one of your enzymes would have worked you might have got a single band with linearize confirmation. Check your enzyme activity and also use right buffer. Good luck

Sal1 is a pain to deal with. It does not cut as efficiently. I digest my vector using Sal1 for 5 -7 hours, 37 degrees. I have tried digesting 2 hours but it did not give complete digestion. I am done with Sal1 after this project. It has caused much more pain than I would expect.