Hi @outofshape
I tried to reproduce the bug but with no luck. I tried with excel activities 2.12.3. and 2.16.0 both working fine.
HRESULT: 0x800A03EC means that you’re trying to access something which can’t be found in excel so I don’t think it might be connected to [Use system separators] option. But that’s an interesting foiunding.
Did it happened once or have you tried running the flow with “1, 3” many times and it always failed?