Problem with h2root


I am trying to use h2root to convert ntuples to trees. i have used it successfully in the past on a group of files but when I use it now on the same batch, it seems to correctly copy the header information but none of the entries. After the h2root command, i get the following:

RZOPEN. Cannot determine record length - EXCHANGE mode is used.
Converting directory //example
Converting CWN with ID= 2, nentries = -1

The “nentries” variable should be around 8000. Is it possible that the files were altered in some way so that the nentries variable was changed but the file remained otherwise intact?

Any help would be greatly appreciated.

Thank you,


Could you tell me a public area from where I can pick your hbook file?


When looking at your hbook ntuple id=2 with hbook or paw,
I see that this ntuple has -1 entries. No idea how you can get it!
As a result, the ntuple is not converted to root


yes, I am aware of the entries = -1 problem. however, the hbook file I sent you was one of many that as of a month ago converted perfectly fine to ROOT. The file is 2.3 MB, indicating to me that the data is still contained within it. My question is then, is it possible for the file or h2root to somehow be --for lack of a better word-- confused into thinking that Nentries = -1 and not ~5000?

As I said, this problem is not related to h2root, but a problem in the original hbook file.
Olivier will have a look to your file once he will be back end of August.


Rene et al,

Thank you for the time and effort that you took to look into my problem. It turns out that the files were corrupted like I suspected and I was able to recover them in PAW.

Thanks again,