Image: iStockphoto/gorodenkoff

The Parallels Desktop application, better known as a hypervisor, aides computing by leveraging the hardware resources of a device to efficiently run more than one OS at the same time, from the same system. Macs using Parallels can create any number of virtual machines (VMs) and run them sequentially alongside the underlying macOS to take advantage of the best that all OSs have to offer.

Parallels is not a large application, and its package-based nature makes installation a breeze for both manual and managed deployment scenarios. The real issues that can grind Parallels to a halt and prevent it from working properly–and conversely keep your VMs from working as well–stems from the multiple preference files used by the app to store configuration and settings information for both the app itself and the VMs it hosts.

SEE: 10 essential apps and utilities for your Mac (free PDF) (TechRepublic)

However, don’t abandon hope just yet. Even the most corrupt of installations–which can lead the app to refuse to launch existing VMs or create new ones, or seemingly lock the administrator out of the hypervisor altogether–may be overcome with a little careful pruning that uninstalling the application and reinstalling it don’t seem to quite clear out. Using the helpful tips below, clearing the problem will get your VMs operational in no time.

  1. Log on to the affected Mac with admin credentials.
  2. If a current backup of the virtual hard drives that store your VMs has not been performed, best practices would indicate one should be made before proceeding.
  3. Navigate to the following path: /Library/Preferences. Delete the Parallels directory recursively.
  4. Navigate to the following path: /Users/Username/Library. Delete the Parallels directory recursively.
  5. While in the same directory as step four, locate and delete all .plist files that pertain to parallels, titled com.parallels*.plist, with the asterisk representing a wildcard entry for various settings relating to specific portions within Parallels.
  6. With the Parallels application now having had its core preferences and settings files removed, empty the trash to permanently delete the purged files.

From here, Parallels may be reinstalled or updated, if necessary. Since the purged files will be replaced with new, clean versions, existing pointers to the virtual hard disks and the VMs they contain will be initialized. Reestablish these links by recreating the VM preferences but pointing them to the existing virtual hard disks. This will ensure that the VMs remain unmodified, but able to launch as intended.