Does the file shows an Indesign icon in explorer? If not, try to right click, select open with and see if you can select adobe indesign CC as the default program. If you have CS6 installed too, only one of the two will let you open the files by default.
Thanks Gert. I've both versions of InDesign CC. I've uninstalled the x86 version and now 64bit opens the file correctly. Thanks again.