ECW image files created in ERDAS IMAGINE 2016 no longer work in other third party products.
There have been many improvements between ECW versions 2 and 3. In ERDAS IMAGINE 2016 the default version of ECW is v3. In earlier versions of ERDAS IMAGINE the default ECW version was v2. If necessary the ECW version can be changed to v2 using the IMAGINE Preference Editor. ERDAS IMAGINE File tab > Preferences
In the Prefernece Editor under the File Formats section select the ECW Image Files category and change the Create ECW Version preference to ECW v2. Keep in mind using version 2 ECW images will not provide the performance benefits offered in version 3. As the ERDAS ECW/JP2 SDK Desktop Read-Only product is provided free of charge, we highly recommend that the third party products update their ECW support to the latest version.