Why are a lot of chunks missing?
uNmINeD can only show chunks that are already saved in the game.
Bedrock Edition saves much less chunks than Java. Increasing the simulation distance and walking around in the game could help.
World pregenerator tools or mods for Java Edition (Chunky) can also be used to fill the missing areas.
Is it safe to use uNmINeD while Minecraft is running?
uNmINeD itself cannot screw up or modify world files, but Minecraft may have algorithms that do not like other applications opening files that Minecraft is currently using, which may lead to data loss within the running Minecraft instance and cause corrupted world files.
It is always a good idea to completely close Minecraft before using uNmINeD or any other external tools, and to back up your worlds regularly to avoid data loss.
Java Edition: It is most likely safe to open a Java Edition world in uNmINeD while playing the same world in Minecraft, as no one has ever reported an issue in the 10+ year history of uNmINeD, but it is generally not recommended.
Bedrock Edition: According to a user report from January 2023, opening a Bedrock world in uNmINeD while Minecraft is still running can lead to world corruption and data loss. Always close Minecraft completely before opening a Bedrock world in uNmINeD!
Is uNmINeD a malware/virus?
No. Some cautious antivirus tools may consider it “dangerous” because it is a less common software that relatively few people download, and it is not signed by a certificate because software signing certificates are expensive.
If your antivirus software says it is a malware, send them the downloaded package for analysis, so they can improve their software to have fever false positives.
Be careful not to download uNmINeD from anywhere other than this site (unmined.net). There are plenty of malicious sites that offer fake minecraft tools for download.