Mounted virtual drives are virtual devices created by specialized software that mimic physical drives but use files (like ISO or VHD) or remote storage instead of physical media. Searching across them means examining the contents of all currently active virtual drives simultaneously, similar to searching across multiple physical hard drives or partitions visible in your file system. This differs from searching within a single virtual drive or a physical drive because it aggregates results across all mounted virtual instances.

In practice, if you mount several software installation ISOs as virtual CD/DVD drives, you could search across all of them to find a specific driver file. Similarly, developers might mount multiple virtual hard drives (VHDs) containing different project versions and search across them all to locate a specific source code file. Common tools enabling this include native OS features like Disk Management (Windows) or Disk Utility (macOS), and virtualization platforms like VMware or VirtualBox.

Searching across mounted virtual drives offers significant convenience, especially for accessing files bundled in disk images without manually extracting them. However, performance depends heavily on the host system's resources and the virtual drive software's efficiency; searching multiple large virtual drives simultaneously can be slow. Future advancements in operating system integration and faster virtualization technologies promise improved speed and reliability for this common task.