Report builder no longer opens

Hi,aduguid ,thanks for your concern about this issue.

Your answer is excellent!
And I would like to share some additional solutions below.

Hello,dasimon .I am glad to help you.

According to your description, you have encountered a problem with your download of Power BI Report Builder not opening properly.
According to the details, it seems that it is because Power BI Report Builder encounters an unhandled exception at startup, possibly due to a mismatched or missing version of one of the dependent libraries.
Here are my suggestions, which I hope will be helpful to you.
1. Ensure that you have the correct version of .NET Framework installed on your system. note that the version number needs to meet the version number of your installed
Power BI Report Builder.
2. Try installing the problematic version of Power BI Report Builder on another computer to see if the problem is due to the version of Power BI Report Builder or a problem with the current configuration of your computer system. This will allow you to quickly pinpoint the problem.
3. If you need to try to delete the original version to re-download, you'd better first backup some important data, and then clean up the registry, uninstall and reinstall the software, the registry may remain in some old configuration. You can use registry cleaning tools (Ccleaner and other third-party disk cleaning tools) to clean up the registry. (Note that important information should be backed up in advance).

Here is the corresponding issue, hope it can help you.
URL:
Report Builder wont start up. - Microsoft Q&A
Applications Fail to Start with Kernelbase.dll error - Microsoft Community