People often give that advice. However, the hard truth is that assets do not cause serious issues. *Missing* assets sometimes do, if the asset that was lost was placed in the city. Therefore, I recommend keeping the assets that are used in the city.

Some advice:
- get back any lost assets that you have placed in your city, if any. The assets report helps with this.
- check your mods, if any obsolete or old ones
- try the Safe Mode loading options (in the options dialog of this mod).

Sorry for the late reply.