Solution for "Japanese IME is not ready yet" on Windows 10

A non-Japanese version of Windows has a bug that prevents you from installing the standard Japanese dictionary file. As a result, even if you add "Japanese" to the Language on Windows, the warning "Japanese IME is not ready yet" will appear, and you will not be able to type in Japanese (you cannot use Japanese IME).

The solution depends on whether you have a Japanese version of Windows or not.

Check if the above applies to your PC

On the taskbar of Windows, enable the Japanese IME and right-click on the [A] button.

If you can't input Hiragana after selecting [Hiragana], it means the standard Japanese dictionary file SDDS0411.DIC is not installed on your PC.

Solution if you have a Japanese Windows PC

Go to C:\Windows\IME\IMEJP\DICTS on your PC with a Japanese version of Windows and copy the files with ".dic" such as SDDS0411.DIC to C:\Windows\IME\IMEJP\DICTS on your PC with a non-Japanese version of Windows, and reboot.

This will make the Japanese IME work, but you may not be able to convert from Hiragana to Kanji. In that case, switch the IME to Japanese IME on the taskbar, then right-click [A] or [あ] to open [Properties].

Click [Advanced].

Click [Repair dictionaries], and reboot.

If the Japanese IME still does not work properly after this, open Start menu -> Settings -> Time & Language -> Language -> Japanese, select [Restore] for [IME default settings], and then reboot.

Solution if you do not have a Japanese Windows PC

Unfortunately, there is almost no chance that you can install Microsoft Japanese IME. Instead, the second option will be Google Japanese IME. It is almost the same as Microsoft IME in terms of usability. However, it sometimes happens that Google IME does not work on Word files with comments or track changes.

If you would like to try Microsoft Japanese IME in a slim chance, here is how to install the on-demand Japanese input package provided by Microsoft.

(Click on the Start menu) Type Command Prompt in the search window on the taskbar. Right-click on Command Prompt in the search results, and then click Run as Administrator. In the Command Prompt screen, type the following command.

DISM.exe /Online /Add-Capability /CapabilityName:Language.Basic~~~ja-JP~0.0.1.0

This will start the download and installation of the on-demand Japanese input package. However, on Windows 10 version 20H2 or later, you should get an error. If it works, please share your solution in the comments section below.

日本語

日本語の解説ページもあります。