A "last exception" file is created by Sims 4 itself as an error report. These files are found in the Mods folder.
The mod Better Exceptions by TwistedMexi creates a more detailed, differently organized error report when Sims 4 creates a last exception file. These files are found in the Mods folder. They include more information than the last exception file does (about your mods especially). You can take them to the TwistedMexi Discord server for help reading them.
The mod MC Command Center by Deaderpool also creates a more detailed, differently organized error report when Sims 4 creates a last exception file. These files are found in the same folder as your MC Command Center files are in. You can take them to the Deaderpool Discord server for help reading them.
None of these will search for broken CC, although Better Exceptions can help identify a CC file. To do that, you can use the "50-50" testing described here: https://forums.ea.com/discussions/the-sims-4-mods-and-custom-content-en/re-info-how-to-use-mods-and-cc/9360660#M58782