Cannot Open More than 20 Files Concurrently Using a Client Mapped Drive by Default

You cannot open more than 20 files concurrently using a client mapped drive by default.

This soft limitation is configurable on the client side using a registry key.

Caution! This procedure requires you to edit the registry. Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. Back up the registry before you edit it.

1. Create a REG_SZ with the name MaxOpenContext under the registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\ICA Client\Engine\Configuration\Advanced\Modules\ClientDrive

2. Set this MaxOpenContext to the maximum number of concurrent client device mappings you require on that client device.

There is a soft limitation on the Presentation Server Client to limit the maximum number of open files using Client Device Mapping (CDM) drives.
If an application receives a denied message from CDM to open the 21st file, then the application can display any message of its choosing. Typical messages include "The file cannot be found" and FileExcep.m_IOsError: 1450.

Note: The error messages in this article may have different root causes not related to the 20 concurrent file limitation on the Presentation Server Client.

CTX238200 – How to Troubleshoot Client Drive Mapping