Put the summary of the bug you're having here
I expected that it changes the Recource Pack
It Crashed
1. I launched Minecraft and go in the Texturepack Menu
2. I clicked on a Recource Pack what I converted from a Texture Pack
3. Then it loaded and crashed after it was finished
Based on a crash report provided in this issue, I believe with high certainty that this report may be a duplicate of MC-17852. You can view all information known about this specific crash at MCX-680.