I am trying to calculate the coverage of a ChIP data set over a very limited set of gene coordinates. I have very simple bed files for both (after trying to eliminate any cause of the error) that are just the bare bones "chr start end" columns, and every time I run the command:

    bedtools coverage -a a.bed -b b.bed

 I get this error:

```
ERROR: Received illegal bin number 4294967295 from getBin call.
ERROR: Unable to add record to tree
```

I used grep to search for this number and it's nowhere to be found in either of my files, which makes sense given that my genome isn't that big. So why am I still getting this error?

Thanks for your input!

The BED files look reasonable.

Maybe there are invisible characters somewhere in the file? Can you try running `mac2unix` or `dos2unix` on them?