I reported this bug yesterday, and it was erroneous closed by someone who stated that I was using an older version of Minecraft and therefore was not entitled to support.  This has now been proven to be untrue:  I completely removed Minecraft from my laptop, redownloaded it, and reinstalled it.  The error still persists, and it persists on all my computers, not just one.

There is a CURRENT feature of the 1.14 Launcher that allows a person to choose to run any previous version of Minecraft so they can play their old worlds (see attached image).  For some reason, the 1.14 version of the launcher broke this functionality.  Trying to launch older Minecraft versions causes a crash error "saves folder already exists".  (See second attachment) This error is independent of whether the saves folder is actually there, or who created it.  It also does not depend on the configuration file.  I have tried all conceivable variations.  As long as this feature is broken, I am stuck on 1.14 - I cannot back out.  I currently only have one remaining computer cut off from the internet to avoid an update.

Please take this bug seriously.  It's the first time in my many years of playing minecraft I've been unable to do this.  (I've been using minecraft since 1.7, and it's by far my favorite game and my favorite pastime.  Not all my computers are powerful enough to run modern minecraft versions following the flattening - in fact, none can run it perfectly.)