Does this work now?
AFAIK it is, or at least was some time ago, borked / intentionally disabled by FDEV.
Hope backing up one's own cahce is enough to save it, and using downloaded won't prevent its later use...
This does not work, and even if you had the old one saved and tried to use it, it would mostly be truncated to a few thousand systems making it somewhat useless. The reason given was something along the lines of "giving an unfair advantage to PC players over consoles"
They also broke - apparently unintentionally - importstars.txt method of fixing your own visited stars cache. According to support (and dev), it should be working. There was an issue in the tracker to get it fixed - but obviously it didn't win the popularity contest and expired.
There are things you can do instead though. You can try
EDJP which can tell you if your selected system is in EDSM or not before you jump to it. Other exploration tools are available