ExcelDNA sample not working in any bitness / packness - "Cannot be run in DOS mode"

Hi Govert,

I am Pavel, CTO from Velixo. We're sponsoring the ExcelDNA project on GitHub, I hoped I could reach out to you directly to troubleshoot, potentially with the client since it reproduces on an XLL from DNA samples.

I built the AsyncHelloWorld-Addin sample on VS2022:

[AsyncHelloWorld-AddIn.zip](https://github.com/Excel-DNA/ExcelDna/files/9238133/AsyncHelloWorld-AddIn.zip)

Basically none of the XLL packages (built in Release | AnyCPU) configuration work for a small subset of our customers.


They are not on ARM, it's a Windows x86-64 architecture machine.

My findings so far:

- They're on Excel 365.
- Even a barebones ExcelDNA addin does not work, in any bitness. Regardless whether packed or unpacked. This excludes the hypothesis that it's in any way related to missing dependencies in our Velixo add-in.
- Launching Excel as admin doesn't help.
- Their trust centre does not prohibit add-ins.
- The add-ins were built on my machine (x86-64) in Release | AnyCPU mode.
- All problematic clients run a Surface Laptop or another Surface device, however the processor is not ARM. It's Core i5-8250U for one client.
- The client has Trend Micro antivirus installed. Its logs showed nothing and there were no security warnings when opening XLL or unzipping the archive.

I am completely at a loss at this stage and the client is blocked from using our add-in on the new machine.

I was wondering if you could help @govert; if it's beneficial I could loop you into our support conversation with them..