A maximum number of 25 sessions can be active at the same time on Excel Services when you enable anonymous access to a SharePoint Server 2007 Web site

When you enable anonymous access to a Microsoft Office SharePoint Server 2007 Web site, a maximum number of 25 sessions can be active at the same time on Excel Services.

SharePoint Server 2007 supports anonymous access by mapping anonymous users to a single user account. Excel Services uses this user account to request all Microsoft Office Excel workbooks for anonymous users.

By default, the maximum number of sessions per user is 25. This number is set at the shared services provider level. It is not based on individual trusted file locations. Therefore, only 25 sessions for anonymous users can be active at the same time on Excel Services. This is true even if the Excel workbooks are in different trusted file locations.

To resolve this issue, increase the maximum number of sessions per user. To do this, follow these steps:

1. On the computer that has SharePoint Server 2007 installed, click Start, click Programs, click Microsoft Office Server, and then click SharePoint 3.0 Central Administration.
2. Type a valid user name and password, and then click OK.
3. On the Central Administration page, click Application Management.
4. On the Application Management page, click Create or configure this farm's shared services.
5. Click the arrow next to the shared services provider that you want to modify, and then click Open Shared Services Admin Site.
6. Type a valid user name and password, and then click OK.
7. On the Shared Services Administration page, click Edit Excel Services Settings.
8. On the Excel Services Settings page, type the maximum number of sessions per user under Session Management, and then click OK.

This behavior is by design.