What is the current behavior? This only happens on the IIS server and not my Visual Studio machine. I get the following stack trace when I try to run the XlWorkbook.SaveAs(memoryStream) extension.

The Object reference not set to an instance of an object error is a common Windows issue from Microsoft Visual Studio. This error occurs when a Visual Studio object is absent, null, or inaccessible.

Object reference not set to an instance of an object. Copy errors encountered, copying will continue: 1 error(s) reported. Copied: PSD001:\Selection Profiles with Replace option Copied standard ...

Ошибка в Unity NullReferenceException: Object reference not set to an instance of an object ...

Excel was installed without admin rights. Conflicting plugins. Corrupt Excel installation. Variable or object hasn’t been defined correctly.