Originally Posted by jsrockit
Time to do this again...
Still the same for LR 6 right?
Yes, it's the same as it's always been.
Lightroom finds image files by reference, the file path is stored in the .LRCAT file. Presuming that you have all your image files stored on external file volumes and that the file path to the image files remains the same on a new system*, all that's really required is to move the entirety of a Lightroom catalog folder from one system to the other and then tell Lightroom what catalog folder to use when it is launched. (In Lightroom Preferences, Presets tab, you can also choose whether to store presets with the catalog, limiting access to them to just that one catalog, or leave them in a central location for use with all catalogs. If you have "Store presets with this catalog" checked, the presets folder is in the catalog folder as well; if not, you also need to move your presets from the central Lightroom Presets Folder on the old system to the new system into the matching folder that the Lightroom installation created there.)
* A nuance on the filepath naming is that on Windows systems volume labels are optional. If your Windows system volumes are not labeled, Lightroom uses the letter designation (eg: "E:" or "F:" or "H:", etc) for identifying volumes, which can cause some problems with filepaths to external volumes that are assigned letter designations dynamically at mount time by the underlying hardware and file system protocols. The solution to this is to always add volume labels to your Windows volumes, then the default is for Lightroom to prefer the volume label over the letter designation. This issue does not exist on macOS systems since all volumes are labeled (named).