In Strategy Web > Preferences > Project Defaults > Export Reports there are two settings that control the maximum number of cells to export: "Maximum number of cells to export to plain text" and "Maximum number of cells to export to HTML and Excel with formatting". However, the maximum number that can be entered in by default is 9999999 (7) and 99999999 (8), respectively. Entering in a greater number will throw a Web API error, as shown below:

The Strategy SDK can be used to increase these default limits. The absolute limit of the Web API is 99999999 (8) and 999999999 (9) for "maximum number of cells to export to plain text" and "maximum number of cells to export to HTML and Excel with formatting", respectively.
Perform the following steps to accomplish this:
1. Open the Web Customization Editor (WCE) > Application Settings > Strategy Web Configuration > Web Configuration Settings > System Definitions
2. Open the "exportMaxCellsPlainText" and change the field "Maximum" under Other Settings. Note: the default max value is 9999999 (7); the absolute maximum that can be set without throwing a Web API error would be 99999999 (8).
3. Repeat with the "exportMaxCellsHTML". Note: the default max value is 99999999 (8); the absolute maximum that can be set without throwing a Web API error would be 999999999 (9).
4. Save and restart the application server.
After Customization:

The example provided in this document is provided “as-is” to the user and assumes that the user:
PREREQUISITES:
For the sample to work, the Strategy Web JAR files must be accessible by the Java Runtime
Environment. The Strategy Web JAR files can be found under:
ADDITIONAL INFORMATION:
The Strategy SDK allows you to customize the standard Strategy Web interface, and extend and integrate the Strategy business intelligence functionality into other applications. However, before changing the way Strategy Web products look or behave, it is helpful to understand how the application is built. For more information regarding the Strategy Web architecture or the process of customizing Strategy Web, please refer to Strategy Developer Zone (https://community.strategy.com/topic/0TO44000000FliLGAS/sdk).
To access the Strategy Developer Zone, you must have access to the Strategy Knowledge Base, you must have purchased the Strategy SDK, and you must be current on your Strategy maintenance agreement. If you are a US-based business and believe that you satisfy all three of these conditions but you do not have access to the Strategy Developer Zone, please contact Strategy Technical Support at support@microstrategy.com or at (703) 848-8700. If you are an international business, please contact Strategy Technical Support at the appropriate email address or phone number found at https://www.microstrategy.com/en/support/contact-support.
CUSTOMIZATION WARNING:
This customization is provided as a convenience to Strategy users and is only directly applicable to the version stated. While this code may apply to other releases directly, Strategy Technical Support makes no guarantees that the code provided will apply to any future or previous builds. In the event of a code change in future builds, Strategy Technical Support makes no guarantee that an updated version of this particular customization will be provided. In the event of a code change in future builds, Strategy may not be able to provide additional code on this matter even though this customization is provided at this time for this specific build. For enhancements to this customization or to incorporate similar functionality into other versions, contact your Account Executive to inquire about Strategy Consulting assistance.