I suggest you to go to Settings-platforms-Android-Multi texture Formats. There you can select which Formats to include in your build.Why Multi?-Because texture decompression is on Hardware Level. The upper compressions Format on the lits is the worst ETC1. Just dont use it. I suggest you to click ETC2, ,ATC and PVRTC to cover most devices. I am not a pro, but your message seems to state that the ATC Format is not natively supported (therefore baaaaad). When you go to File-Package Project- Android - you see a list where you can choose to compile for ONE specific texture Format (not suggested) or on the top of the list “Multi texture Formats”. There you can see all those are the ones you checked before in Settings. Good luck
Format
Description
ETC1
Supported by all Android based devices but cannot compress alpha textures (they are stored uncompressed). Recommend using an RGB and a separate alpha texture if need alpha to get better compression.
ETC2
Supported by all OpenGL 3.x class devices and supports alpha compression.
ATC
Supported by Qualcomm Adreno GPUs and supports alpha compression.
DXT
Supported by Nvidia Tegra GPUs and supports alpha compression.
PVRTC
supported by PowerVR GPUs and supports alpha compression.
ASTC
Latest Texture compression format allowing more quality control by specifying block size and supports alpha compression. Available on some devices at this point and will be required for Vulkan Level 1.
I corrected my own problem when I realized I was clicking on “Package/Android ATC” instead of “Pakcage/Android ASTC”. I feel a bit dumb, but that’s corrected!