It is 11082 en-US? Those are Optional features, not system language pack. The 11082 language pack can be installed offline only. Then the Optional features. You can 1. mount the en-US install.wim 2. add Japanese language pack Code: dism /image:X:\MOUNT /add-package /packagepath:X:\ja-JP.cab 3. set-skuintldefaults as ja-JP Code: dism /image:X:\MOUNT /set-SKUIntlDefaults:ja-JP 4. (optional) remove en-US language pack and Optional packages Then put this install.wim to Japanese 10586 ISO\sources and save as a new ISO to upgrade.
That download progress bar used to be the "Language pack" then it asked if I wanted to install... I'm also looking just for the IME features, not converting windows over to JP fully, seems the pack did install finally after stoping it, rebooting and hitting install again.
That is Microsoft-Windows-LanguageFeatures-Basic-ja-jp-Package~31bf3856ad364e35~amd64~~10.0.11082.1000 The System language pack should be added from Control panel. But 11082 has install issue. Are you using 11082?