Good old Office Web Apps

[Mathieu Desjardins]

Hi everyone, sorry to bring back that kind of subject but I am facing a little issue. Some background, we still need to use our SharePoint 2013 environment for some time and I have to get rid of our old server 2008 R2 that are still around. 

So I added a new server 2012 R2 for some test and I have installed the Office Web Apps on it as proposed on a MS guide (Deploy Office Web Apps Server - Office Web Apps Server | Microsoft Docs). I am running it as a single https server. The Apps are not installed on the system drive, they are on the D drive.

I have ran the commands to link it to the dev SharePoint 2013 environment and all seems to be fine except for Excel documents that are not able to be opened.

The errors I have in the event viewer are There was an error in communicating with Excel Calculation Services http://ServerName:809/ecs/ExcelService*.asmx exception: The underlying connection was closed: An unexpected error occurred on a receive.
[Session:
User: NT AUTHORITY\NETWORK SERVICE]. event ID 5239.

I have compared the environment with the current prod and I can't seem to see any differences.

Both environment seem to:

1. Run the AppPool as NetworkServices. 
2. Not using the Excel Calculation Services (not listed in SharePoint Central Admin)

I have notice that the site being mentioned in the error is http and not https.

So, is there a way to validate that we are not using the Excel Calculation Services?

Is there someone with some experience in configuring web apps that can give a hand on that one?

Edit: I have reinstalled my Office Web Apps on the same server but this time on the C drive, same problems:(

Thank you very much

Mathieu

[#2]

@Mathieu Desjardins 

OK so I did found the solution to my problem. 

It look like when using a version of .net framework superior to 4.5.2 you need to Unable the legacy JIT:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework
Then, add the following:
Value name: useLegacyJit
Type: DWORD (32-bit) Value (also called REG_WORD)
Value: 1

After activating that setting and did a IIS reset, the excel workbook where correctly opening. 

Maybe that part should be added to the documentation page? I know the product end of life is 2023 but still relevant information to have.