Improve known issue (#17792)
- Explain the actual symptoms (the password will always be rejected) and avoid an ambiguous use of a modal verb ('cannot'). - Explain the workaround: people might loose work if they realize half way through their session that they cannot install an Additional Software. - I don't expect the command line trick to be very useful. - Link to what our terminology means ('administration password'). - Clarify what non-English means.