Not by itself. MEGA is a legitimate service. However, downloading copyrighted or cracked software is illegal in many jurisdictions. The act of accessing a shared folder is not illegal, but what you do with the files might be.
When putting together full content in a MEGA folder, consider these security and organizational tools: https meganz folder cp upd portable
Pull the standalone package or run an extracted user-space copy. For example, download the binary from the MEGA repository and isolate the raw application folder. 2. Initializing the Background Server Not by itself
While the software itself is a legitimate open-source project, downloading and using any executable file from the internet requires caution. The act of accessing a shared folder is
When users share a "folder link," anyone with the URL (and the corresponding decryption key, which is usually embedded in the link) can view, download, or import the contents directly to their own Mega account.