Downloading "pre-activated" or cracked software from third-party sites is highly discouraged by cybersecurity experts for several reasons:

You will not receive critical security patches or bug fixes, leaving your computer vulnerable to new exploits.

While you may find sites offering "activated" or "cracked" free downloads of Lightroom 6.1, these pose significant security and legal risks. Official installers are no longer hosted on Adobe’s servers. Risks of "Activated" or "Cracked" Downloads

Since Lightroom 6 is no longer for sale or supported, consider these legitimate paths: End of Support | Lightroom 6 Downloads and Syncing

Modified code often leads to frequent crashes, missing features, and performance issues that can corrupt your photo catalogs.