Confirm this is Plesk for Windows and that dedicated-pool management is included in the subscription. Record current pool settings, application architecture and any in-memory session dependence. Plan a maintenance window because changing or recycling the pool can interrupt active requests.

1. Open the domain Dedicated IIS Application Pool for Website page and review whether the pool is enabled and which applications use it.
2. Enable the dedicated pool when permitted. Confirm the intended isolation scope before changing a shared pool used by other sites.
3. Keep the worker-process count appropriate to the application. Increasing it creates a web garden and can affect in-process sessions, caches and resource use.
4. Review idle timeout, CPU limits and recycling triggers. Choose limits within the service allocation and avoid an aggressive recycle interval that hides an unresolved memory leak.
5. Save, then test a fresh request and a session-dependent workflow. Review whether the application requires 32-bit components before changing its architecture mode.

Confirm the site runs in the intended pool, requests succeed and expected session behaviour survives normal operation. Monitor memory and CPU over a representative period. A pool being started does not prove the application has completed a healthy startup.

If requests fail after the change, restore the recorded setting and inspect Windows Application and System events. Do not solve a startup error by granting the pool administrator rights. If the management control is absent, ask about plan permissions rather than modifying shared IIS settings outside the supported Plesk workflow.

• Diagnosing an IIS application pool that keeps stopping
• Fixing a Plesk Windows website permission problem
• Hosting an ASP.NET Core application on Plesk for Windows
• Setting the default document for an IIS website in Plesk

• Plesk: Plesk For Windows Setting Up Iis Application Pool
• Plesk: Iis Application Pool