Cannot write histograms in the file because of opening another root file

With the latest v616 (tip of the patch branch), I can not reproduce the problem :frowning:

The ‘annoying’ file can be recognized with:

si = dynamic_cast<TStreamerInfo*>(gFile->GetStreamerInfoList()->FindObject("TH1D"));
si->GetCheckSum()==4189148831 && si->GetClassVersion() == 2

and are fixed (in v6.16) by commit 74a1f65efc39e79b57d3104d6d288b51e913dcfa

The version affected are:

v6.14/00, v6.14/02, v6.14/04, v6.14/06, v6.14/08,

The tip of the patch branch v6.14 and v6.16 and the version v6.18/00 and later are not affected

The problem is due to commit 8c9c1a3fbe3a1c5704635f8941abeb9596104c77 (Change to onfile format without a class version upgrade).

And yes this means we need to tag v6.14 and v6.16 very soon.