When you have two or more office versions installed (or not fully uninstalled) the resources they share can cause confusion when you try to install peripheral software. You need to ensure that the 'preview' version is completely uninstalled, reboot and then repair your paid for version, before attempting to install the language pack.

If you search the web for uninstall your undisclosed preview version completely, you will find a Microsoft 'fix-it' link to remove it.

If the preview version is the same as your paid fro version, it will probably remove both versions so then you need to ensure that you have the media and product key to hand to enable you to re-install before proceeding.

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Graham Mayor - MS MVP (Word) (2002-2019)
Visit my web site for more programming tips and ready made processes www.gmayor.com