There are two known problems when working with Excel Interop.
1. After having used Excel and shut down your application, an Excel process still "hangs" in background.
2. When your Excel installation is English (en-US) only, but your Windows is configured for a different language (e.g. de-DE), some calls to the Interop fail with a COMException.
Luckily there are also workarounds for this problem which you can easily find when googling for them. Two classes have been handy for me to encapsulate these workarounds.![]()
