SFV / CRC Failed / hash check failed
Troubleshooting guide for failed CRC check.
Notice: Whenever turning off the hash-check is advised in this guide, that's rather a workaround than a solution.
Follow the instructions and try to solve the reason behind your CRC failure so that you can leave this setting enabled!
2nd notice: This guide assumes that you're downloading multipart .rar or .zip archives.
If you're downloading single files such as .mp4 videos, chances are very high that even if the file is damaged, it is playable just fine meaning you will not be able to easily identify it as a broken file.
1. Exclude hardware issues by checking your HDD/SSD and RAM.
Especially broken RAM can cause issues during CRC checking!
For RAM checking, software like Memtest86 is recommended.
2. If you are downloading via multihoster, chances are that the multihoster is sending a different file than JD expects.
The file itself is correct but JDownloader will use the hash of the original source to compare agains the one from the downloaded file and thus fail.
You can turn off the hash check temporarily, reset some failed files, re-download them and see if you can extract them without any issues --> Chances are, your issue is caused by the multihost.
In this case, you can contact our support- and the support of that multihost so we can implement it properly and avoid these errormessages from happening to you.
3. In very rare cases, hash check can fail because JD simply gets a wrong hash to use for checking.
This won't be easy for you to find out but again you could temporarily turn it off, reset and re-download affected files and see if they're okay.
4. Make sure that your Firewall/AV scanner does not interfere with JDownloader - this may also cause CRC issues.
Check this by e.g. completely disabling your Firewall and downloading the affected files again afterwards.