Same problem:

When we create a new domain in Plesk, the server automatically sets the app pool to 32bits. But most of our clients ask for the 64bits app pool, and they can´t change it by themselves in their plesk.
On top of that, accessing a domain with 32-bit app pool crashes the application pool. This means we have to switch each domain (automatically generated from script) manually to 64 bit.

Fewer and fewer people are using 32-bit vs 64-bit. I would recommend Plesk use the default application pool template available in IIS. It's the fastest way to solve 80% of the issues.

My application pool default is 64-bit yet Plesk forces it to 32-bit and I've tried editing the template files, it seems it's a hard coded Plesk thing. Please just remove the hard coding and let us get on with business.

My Websites use only 64 bits application and I need set on IIS this option.

For ASP.NET Core 2.2 deployments we need 64 bits and Plesk automatically sets the app pool to 32 bits. Clients cannot change this and are unable to run their applications.

See this thread https://github.com/aspnet/AspNetCore/issues/4413#issuecomment-444624391

Allow 64 bits Apps to use more of 2 GB RAM

I need the same case,
When we create a new domain in Plesk, the server automatically sets the app pool to 32bits. But most of our clients ask for the 64bits app pool, and they can´t change it by themselves in their plesk

When we create a new domain in Plesk, the server automatically sets the app pool to 32bits. But most of our clients ask for the 64bits app pool, and they can´t change it by themselves in their plesk. :(

In my case, we have different customers using different pools (32 and 64 bits) - and they can't adjust it using their plesk panels....

My Websites use only 64 bits application and I need set on IIS this option.

allow 32bits application