# “Cannot find file” error when running biber

I'm commuting to using the new biber/biblatex system of referencing. Previously I have been using bibtex as a backend and have tried converting to biber. I'm using MikTeX 2.9 under windows xp sp3.

I compiled my thesis: project name: `Thesis_1`; `backend=biber` is set in the options for `biblatex`.

This runs with the expected reference and shortcut warnings.

Then I run `biber Thesis_1` and get:

``````INFO - This is Biber 0.9.6
INFO - Logfile is 'Thesis_1.blg'
INFO - Found 0 citekeys in bib section 0
INFO - Found 3 citekeys in bib section 1
INFO - Found 132 citekeys in bib section 0
INFO - Processing bib section 0
INFO - Looking for bibtex format file 'References/References1' for section 0
ERROR - Cannot find file 'References/References1'!
INFO - ERRORS: 1
``````

You can see that I have my bibliography file inside a folder called `References` within the project folder and that the bib file is called `References1.bib`.

The file is there of course.

One possible cause may be a bug related to cross-platform compatibility. The file has been called `References/References1`, but a backslash should have been used instead for a windows path. Maybe it's not this at all, but it would be nice to have a fix.

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It works fine for me. And if I had to guess I would say that your problem has nothing to do with subfolders but that you use \addbibressource and forgot to add the .bib at the end. – Ulrike Fischer Dec 12 '11 at 14:36
Yes, Biber uses a platform agnostic library for file paths etc. so it won't be that. It is probably that you are using `\addbibresource` but not fully qualifying your file name with `.bib` as per the biblatex manual. Can you check? – PLK Dec 12 '11 at 20:19
Ulrike and PLK, indeed you are both correct. Adding .bib to the file name resolved the matter, though it was interesting that no problems were caused when using bibtex. I will try and modify the question title and tags so that this might be more helpful to others. If one of you wants to put this as an answer then I will mark it as answered. Else I guess I should close the question. – aghsmith Dec 15 '11 at 12:42
I gave the same answer later so I'll let the first person create an answer. The behaviour of `\bibliography{}` and `\addbibresource` is different - the latter required the extension - perhaps you switched commands when you switched backends? – PLK Dec 15 '11 at 14:39
I didn't actually. I switched commands when I changed from `natbib` to `biblatex` though. I guess it is a case of `biblatex` and `bibtex` being happy with either and `biber` requiring the extension. – aghsmith Dec 15 '11 at 17:09

The issue was that I did not have the `.bib` extension in the `\addbibresource{}` command. It was unneeded when using `biblatex` with `bibtex`, but was needed when using it with `biber`.