@Krzysztof Maz
Hi,
The fastest way to get the upgrade is through Media creation tool or ISO file.
Please download Media Creation Tool from the link below and select Upgrade this PC at the first screen:
https://www.microsoft.com/en-us/software-download/windows10
This will save your files and apps while bringing you up to the latest version by the most stable method. It will also bring all of your Updates current and solve most problems since it reinstalls Windows.
Hope above information can help you.
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