December 2020 Update – Issues Regarding Power BI Report Server October Update
Power BI Report Server Community,
The Power BI product group wanted to provide an update regarding the Power BI Report Server October 2020 update. We thank you your feedback and patience while we work through the reported issues. The October release included a significant update to the Power BI model metadata format bringing it in-sync with the Power BI service. An update to the October release is already available on the Microsoft Download center. We are actively investigating remaining issues and anticipate an additional update available in early January 2021.
To provide more details about the change and known issues, we’re outlining the following::
Review of changes made that are now currently available
Roadmap of expected updates for the January release
Mitigation steps that can be taken for current issues
The Power BI Report Server October release includes the new Enhanced Dataset Metadata format in which all queries will be mapped to objects in the data model. More details about that feature can be found here. With this change, the Power BI Desktop for Report Server will upgrade reports to the Enhanced Dataset Metadata format when edited. As a result, the next time the report is saved it will have the updated format. Desktop authors can opt-out of the new format as noted below. However, this may limit use of new features which are dependent on the enhanced format.
Note that reports and datasets not edited or saved with the October edition of Desktop for Report Server will continue to remain in the existing metadata format. The upgrade will occur only when opened in the desktop editor.
After the initial October release, we received feedback based on the PowerBI forums and the PBI community regarding model metadata and refresh. A set of fixes have been made in the November update available here: link addressing common refresh issues with Enter-Data datasources and model refresh errors. If you are experiencing issues with Power BI Report Server October release and have not upgraded to the November release, we strongly suggest starting with that upgrade.
Please note that we are actively investigating the following known issues. These will include errors during model refresh indicating:
“No credentials were found for the datasource.”
“COM error: mscorlib, An item with the same key has already been added”
“The credentials provided for the SQL source are invalid”
If you are experiencing additional or related issues, we encourage to provide detailed feedback on this forum under a new thread. Or, if business critical, to contact Microsoft support. However, please note the most expedient resolution will be to follow the following prescribed mitigation steps.
If you are seeing the following errors or issues, first try installing the November update, and then try the following mitigation steps:
1. “No credentials were found for the datasource.”
If you are experiencing this issue and have two or more datasources that differ only by the casing of the letters -- I.e. MYSQLSERVER;AdventureWorksDb and mysqlserver;AdventureWorksDb. Some customers have found success using the same casing for each of the datasources and then re-uploading the report
If this does not mitigate the issue, follow the “How to Disable Enhanced Dataset Metadata” guide at the end of this section.
2. “COM error: mscorlib, An item with the same key has already been added”
We recommend following the “How to Disable Enhanced Dataset Metadata” guide at the end of this section.
3. “The credentials provided for the SQL source are invalid”
Note that a restart of Report Server has addressed this issue for some customers. If this does not mitigate the issue, follow the “How to Disable Enhanced Dataset Metadata” guide at the end of this section.
How to Disable Enhanced Dataset Metadata
Note that Desktop authors can control if the enhanced metadata format is used when editing reports. If you are experiencing the above or similar errors, we recommend disabling the options in desktop as follows:
Turn off the Enhanced Dataset Metadata option in Power BI Desktop RS
In Options, under Preview Features, uncheck “Store datasets using enhanced metadata format”
Restart Power BI Desktop for Report Server
Restore the old report from the hidden backup in AppData.
Before the file is upgraded to the new format, a backup copy is saved in the app data folder. For example: C:\Users\myuser\AppData\Local\Microsoft\Power BI Desktop SSRS\TempSaves\Backups.
Open the backup and you should be able to save the old version of the report back to the server.
We appreciate your feedback and patience while addressing these issues. Please continue to post feedback on the forums as we actively monitoring them. Also, check back for updates on upcoming fixes and availability.