Confluence server HTML export files are gibberish: PDF is fine. What is problem?

Question

The HTML export files are opening to a lengthy string of this: PKd§DS/PKPKd§DSIBID/PKPKd§DSIBID/index.htmlÍ™_sÚ8Àßû)öüpÓÎTñ°–0C!i¹k/L ½éSFØkb,Ÿ-’Ë}ú[É6ŠÝ»fZ’É$¶wWÞßJ^¤/ú¿Œ¯Fó/Óå:¼èçÿú!£A~©o%—LÞMÆðròqï"áßù!å1L®áWºNÞÂøUßÌõvvï eÑ¹‘ÉÇˆe!cÒ€0eËò‰™qÉÎü,3@>&ìÜìoiê{³ÒÐ§‹ùÝ” amøý¹1±d±$s42ÀÏï kÅñÐ½4còüf~IºFÁeæ`ùÍBàG4ËÐ0dkF¶¤›HÝp²÷Ä¨øð{àÁ¹‘Ð«<ß“14FÙ¶jM)ãŸ˜E&_™å"K¨å=ckMiÊãÕöMê-ZRc[ÈÐJ*dÆ`–PŸÁ˜IÊ£ìMßTJ5˜¡}ÁD†"°GÑŠ.ªÃÚ‹@©[Åš1_r×ÙKºˆX©öËhÃbŸÍÕã¦`È´^˜+„GZ ÁïìÇ{ø-ëàˆu`èO ÍƒÏÌ&×¾ßï?èš=Åñº¯ÿ44c–ù)OÔÈxÔðzôaòùbÓë«ß.Fs˜M‡£€žiwLÇrìÓÀRF%`ñ”‘–`úÚdwðrÌ|°»¯Á±ìî«ïB‰ú¢ê„*ÀqÙ"5k¬´¤>+üçÐ`ñ¡)¥nmCçˆé Yet, a PDF export appears complete & fully legible. We have tried Chrome, Internet Explorer, Edge, and Firefox but the HTML files are not useable. What is likely cause nd can this be fixed?

Kevin Paulus · Answer

Thank you Nic:
         The export files are not coming out in a zip file just a single html file, I believe all the pages are affected.    There are no discernably coherent words or phrases visible from start to end of the file.

Nic Brough -Adaptavist- · Answer

Thanks for the detail, the main thing I wanted to check there was that it was the built-in export that I also use sometimes, so we're looking at the same thing.

There could be other ways to do it, but we shouldn't need to worry about them, let's stick to the off-the-shelf one.

The standard export drops out a compressed file that contains each page as plain html after you uncompress it.

So, the next question is what you are doing after you have downloaded that single zip?  I wouldn't expect the zip to look quite like what you have, but it could be.

Have you unzipped it all?  Which page.html is showing all this gibberish when opened?

Kevin Paulus · Answer

Thank you Nic,
          I am using the Confluence interface:  
Space tools >> Content Tools >> Export
  From there, selecting HTML, Normal Export.

Is there another way?

At your suggestion, I tried opening with Notepad, wordpad, and Microsoft Word  -- the results were the same.

As for compression, I don't know -- since I am using the Confluence app, if there is any compression, Confluence would be applying it.  How would I determine whether or not there is any compression?