This article is part of our guide to fixing Google Data Studio reports.
Chances are that if you see the error message "Data Studio has encountered a system error" it's because you have an invalid metric.
If you click on See details, you'll see this error message.
This is an example. This is a blended data source where one of the fields is missing (it was removed).
This is another example. This is an invalid metric due to an incorrect math operation. For instance, you may have a typo in your formula.
If you have questions on setting metrics and dimension on Google Data Studio, we recommend you these tutorials: