Lightroom Classic filling up internal drive even when library on external drive

[jordan.reynolds]

There may be an easy solution to this, but I have my lightroom folder being stored on an external hard drive. Recently I have noticed my internal hard drive filling up about 5gb per 64gb card I import to external drive.

Just to clarify here is my proceedure:

Open lightroom

Open Folder (on external drive)

Right click - Import to folder

Select files

Import completes 

External hard drive has then gained 64GB, but internal drive has also gained 5GB.

I never used to have this happen as I'm only working with a 250GB internal drive and 1TB externals. 

Any clues as to where this is going astray? 

[Jao vdL]

where is your catalog itself stored? If it is on your internal drive then what you see is due to previews and such. You can put the catalog on the external ic you want. Also Lightroom uses a cache for quick access that is by default on your internal drive.

[JohanElzenga]

Lightroom Classic creates previews for all your photos, and these previews are stored inside the catalog folder. Previews can take up quite a bit of space. By default the Lightroom Classic catalog is stored inside your Pictures folder on your internal disk, but it does not have to. Like @Jao vdL said, you can also store the catalog on that external disk. To do that, copy the entire catalog folder to that disk, open the folder and double click on the catalog file ('catalogname.lrcat') to let Lightroom know it should use this one from now on. Then you can delete the folder from your internal disk.