End coordinate 195481851 bigger than chr1 size of 195471971 line 13952 of test.bed

This error can be a serious one. Don't simply use the clipping solution suggested by some online threads.

Possible causes and solutions:
1. You mapped your reads to mm9 but used mm10 sizes to feed the bigBed generation script

Solution: use mm9 size file to redo the generation or map your reads to mm10

2. The program you used upstream extended the fragments and they exceeded the end

Solution: use bedClip for bed files and use -clip option for bedgraph files