Root crashes after fitting/iterating on some histograms

I have a directory of root files.
I have a macro that is supposed to iterate over them, doing the following for each:
Create a histogram, fit a gaussian function, integrate the fit function and print out the value.

When I run the macro, the first run goes smoothly but then immediately I get this error message and stacktrace: I’ve checked and the fit should not be empty, so I’m thinking it’s a memory error? I tried naming each histogram something different (appending the file name) but that did not fix the error. I can share the macro if requested.

ROOT Version: 6.18/04
Platform: Windows
Compiler: Not Provided

Could you post a running macro as reproducer?

I’m sorry, what does that mean?

How can I reproduce the error?