Issue

When selecting sources or measurements in a report, it shows "An unexpected error has occurred".

Checking the log under Settings tab > System > System Log shows the following error: "Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster."

Product Line
Power Monitoring Expert 2021
Power Monitoring Expert 2022
Power Monitoring Expert 2023
Power Monitoring Expert 2024

Environment

Reports

Resolution

1. On the PME server, open File Explorer and navigate to ...\Program Files (x86)\Schneider Electric\Power Monitoring Expert\Applications\SystemDataService

2. Make a copy of the existing web.config file and place it in a separate backup folder

3. Open the web.config file in Notepad, then deleted the below highlighted text:

4. Save the web.config file
5. Navigate to ...\Program Files (x86)\Schneider Electric\Power Monitoring Expert\web
6. Make a copy of the existing web.config file and place it in a separate backup folder
7. Open the web.config file in Notepad, then deleted the below highlighted text:

8. Save the web.config file
9. Open the Windows Start menu and search for "cmd", then right-click > Run as Administrator
10. Type "iisreset" (without the quotes) and press Enter to run the command
11. Open the Windows Start menu and search for "Services"
12. Restart the ION ApplicationModules Core Services Host Service

Released for: Schneider Electric South Africa