Hello @n3wjack and welcome to the forum!
Sometimes it works best to “ask” the Internet for reports, by a web search. English version is likely:
“System.IO.IOException” “cyclic redundancy check” (adding more of the message gets fewer hits)
System.IO.IOException is a very generic higher-level mechanism which I think is passing along a lower-level error which I think is saying your hard drive is having trouble. Look at reports and judge for yourself.
I’ve searched much of the code of Duplicati, libraries it uses, and Windows system files, and it’s only in Windows kernel files (which for me are in C:\Windows\System32\en-US – yours might be in a different folder, maybe nl-NL) that I can find the string. I suspect it’s from ERROR_DATA_CHECKSUM_ERROR.
I suggest running some software (e.g. CrystalDiskInfo) that can check the S.M.A.R.T. stats of your drive.