Hello, look at the path where nightly is installed : it's not the same as Firefox 64 bit Stable version. In the list of installed programs, there are two different entries : one for nightly and one another for the stable version. If you chose to uninstall Nightly, the stable version will not be removed (unless you 've installed Nightly in the same folder of Firefox 64 bit stable).

thank you for your advise but I already made the mistake of not having separate folders and I'm sure your way would have worked. i have been using Eversync and Speed dial on chrome and firefox which saved me when I uninstalled nightly it took Firefox with it and to make things a little more difficult I had just bought a new ZTE Max Duo LTE 6" phablet and had Firefox android with e Eversync on it so I ended up with a zillion bookmarks so I deleted the e Eversync on android so I was able to merge my speed dials between chrome 64 and Firefox reinstalled. to make a long story endless it worked. now with your insight I'll know enough to make separate folders from now on,Thanks