Say no more, @Afreije74. I'm here to help you get your QuickBooks back up and running.
We have a tool hub that will help us fix common QuickBooks Desktop issue like yours. Let's first download and install our tool hub and then run the QuickBooks Diagnostic tool from the hub.
Then, let's run the diagnostic tool.
Once done, restart your computer and try reconciling your credit card again. You can learn more about the different solutions when QuickBooks stopped working at this link here: What to do if you can't open QuickBooks Desktop.
I've also added this article about clean install QuickBooks Desktop just in case you need to uninstall. It has detailed steps that you can follow throughout the process. Uninstalling also helps in adding new install files but won't remove your company file.
Please know that we aim to get your reconciliation process complete as quickly as possible. Stay in touch if you need help with anything else. We're here to lend a hand. Take care and have a good one.