Saving files with MakeClass and Tree Doubling

For some bizaar reason, every time that I run the loop from MakeClass it seems to double the amount of total entries in my tree. I use fChain->Fill() at the the end of each event loop. I kludge my way out of this by only plotting half the events in my histograms after I run the loop, though it is quite annoying. MakeClass also seems to randomly abort while trying to do the same thing with more then one file.

I’m also trying to save the tree to a new file after I’ve run the loop and added a few branches. For some reason this is proving to not be a trivial matter. I seem to be able to save the file, which ends up being slightly smaller then the original file, and root aborts when I try to plot from the file, though it seems to load properly. I have the file saving at the end of:

myClass::Loop() {

TFile …;
fChain->Write();
}

Thanks!

My usual request:
Please send the shortest possible running script (and data file) illustrating
your problem.

Rene