While adding extension bb01ff21_dict-sr.oxt (a Serbian Spellchecker) to the LibreOfficePortable 7.1.2.2 (x86), an Error dialog box appears on the screen with a message:
C:\PortableApps\PortableApps\LibreOfficePortable\App\libreoffice\program\..\..\..\Data\settings\user\uno_packages\cache\uno_packages\lu10984k4b7p.tmp_\bb01ff21_dict-sr(1).oxt does not exist.
'Only for me' installation.
After further Investigation, I've found out that in the directory c:\PortableApps\PortableApps\LibreOfficePortable\Data\settings\cache\ there is just one file (skia.log, 23 bytes) with a content:
RenderMethod: raster
Compiler: Clang
But the directory c:\PortableApps\PortableApps\LibreOfficePortable\Data\settings\user\extensions\tmp\extensions\ contains subtree lu69721refbr.tmp_\bb01ff21_dict-sr.oxt\ with an unpacked .oxt.
Even more, I cannot add any another localization extension to the LibreOfficePortable and haven't got a hyphenation at all. So the portable instance of LibreOffice is absolutely useless for me without localization extensions.
I just tried installing it and it worked without issue here. Note that I didn't have a double PortableApps\PortableApps directory on my install (recommended against due to long path issues in apps like LibreOffice). I'd suggest clearing your UNO cache (delete the contents of LibreOfficePortable\Data\settings\user\uno_packages\cache\uno_packages) and extensions tmp (delete the contents of LibreOfficePortable\Data\settings\user\extensions\tmp\extensions).
Sometimes, the impossible can become possible, if you're awesome!