How to fix Samsung Galaxy E

Trying to wipe cache, factory reset the phone, mount /system, flash a ROM from SD card, ADB sideload, everything gives the error multiple times.

Just go for Wipe menu from TWRP home screen and select cache . It will show same error but format will be completed. Then select Mount menu from ...

1. 1. 尝试重刷recovery也不行，从报错上看应该是系统的/cache分区出了问题，用recovery双清也不行，在一篇帖子中发现了fastboot -w的命令：

Hi guys. After a re-boot I have lost my SSD cache. I'm not at home now but something like failed to mount, I got it when I saw I had no ...

Hold only the power button down for 40 seconds or until your device shuts off. After your device is powered off, press the power button for two seconds ...

My TV is stuck in recovery mode and I'm getting failed to mount /cache error. I have tried wiping cache and partitions. Tried to flash rom as well via USB.

In Android System Recovery, I receive a scrawl that states: E:failed to mount /cache (No such file or directory) E:Can't mount /cache/recovery/log E:Can't open ...

Fix Unable to Mount Cache, Data, System, Storage In TWRP Recovery Fastest Method ...

Try fix the failed to mount cache issue, you have to go to recovery menu and mount system and then clear cache again. It will fix the issue.

It does sound like hardware failure as the other says. Try to get the entire device replaced or buy a replacement. No way to know what caused the failure.