tophat dataset number issue

Greetings, I proceed my datasets by tophat, unfortunately, there is an issue with the dataset numbers. Some of them don’t have dataset number (writes ''null. ‘’ at the beginning). So Is there any way the fix this problem? Thank you so much.

We would need more information to answer this question. But the short answer is, please do not use TopHat. Use Star or HiSat2 instead.

Hope that helps,
Bjoern