Some time read a post of SciresM telling what the use of Fat32Format and the Gui version Guiformat was not compliant, but for some of us is more convenient to use it, you can download from http://ridgecrop.co.uk/download.htm.Format your card whit exfat and this tool.
https://www.sdcard.org/downloads/formatter/
After this put your cfw files (whit hekate) on it and boot to hekate.
Format your card inside hekate to fat32 whit the partition tool.
Also if you suspect of a degraded or fault card you can use also H2testW (https://www.heise.de/download/product/h2testw-50539) to check the integrity of all memory.