iMac mouse no longer charges

Thanks. The A1657 is an Apple Magic Mouse 2. Apple started to offer them in 2015 and continued to do so for a number of years. Even if you got one in 2018 with your iMac, the chances that its rechargeable battery is spent is very possible.

However, there still may be some other reasons that the mouse will not charge:

• A defective Lightning cable or charging adapter.
• Debris or corrosion in the Lightning port, preventing a reliable electrical connection.
• A failure of the mouse's internal charging circuitry or a damaged Lightning connector.

Most likely, the internal rechargeable battery in your mouse (you didn't mention the make & model) is depleted. As such, if that is the case, the mouse will need to be replaced.

KandKG wrote:

If I buy a new one just referencing the same model number should be good to ensure compatibility right?

Possibly, but I'm not sure Apple still sells the A1657 Magic Mouse. The latest version: A3204, which was introduced in 2024, requires a Mac that is running macOS Sequoia 15.1 or newer. If you purchased your iMac in 2018, then most likely, it is a 2017 model. If that is the case, it can only run macOS Ventura (13.x) and you will NOT be able to use this newest mouse with it.

One option is to go with another brand mouse, like those from Logitech.