MacBook suddenly running extremely slow

Please download and run EtreCheck (the free version, don’t need the paid version here), and share the results to the clipboard. Then open a new reply here, and press the Additional Text button that looks like a printed page, and paste and post the hardware and software configuration report here. From that, we can get a little more detail about what is installed and what is running here.

Having retails here helps us better help you. Mac laptops with some variant of "Macbook" in the model name have been around since 2006.

If you don't post the requested Etrecheck report, which is our single best tool for effectively helping you with computers we can neither see nor remotely access, then at least tell us your Mac's Model, Sub-model, and OS version.

True "MacBooks" were discontinued in 2019. Current models are:

MacBook Pro

Macbook Air

MacBook Neo

That info is easily available by doing "About this Mac..." from your Apple menu.

For current macOS versions it looks like this:

For older versions:

For REALLY old versions:

We want to help but need more details. EtreCheck is our best source of those details. To help you post the lengthy report, see this:

How to use the Add Text Feature When Post… - Apple Community

Allan

(nearly 79 😳)