using 64bit V7.6.4 on a Windows 8.1 Dell . Once I added a folder under templates, all the templates disappeared even though they show on the recently modified Welcome screen:
[attachment=2]ScreenHunter_14 Dec. 20 12.55.jpg[/attachment]
[attachment=1]ScreenHunter_15 Dec. 20 12.55.jpg[/attachment]
[attachment=0]ScreenHunter_16 Dec. 20 12.55.jpg[/attachment]
Reset gateway did nothing to resolve. Fortunately I was not too far into updates from previous backup. I exported all templates, restored a recent backup then imported templates and all was good again.