I just updated an Acer laptop that had been restored to factory 8.0. Had to download and install 179 updates to 8.0, including two supposedly optional ones, before the 8.1 update would download and install.
That took about 24 hours! Most of that time was spent installing the update and this is not a slow computer.
Is there an 8.1 update download that includes 100% of everything it needs so it can be installed onto a clean 8.0 install?