Please follow the link to help you to fine minimum settings to save the hard drive space of your computer. This might affect the performance of Lightroom.
Also, I would suggest you to store your original images on to a external hard drive to save space on your internal hard drive. You may choose to keep the catalog to the external hard drive as well.
Note : Lightroom does not keep the original files within the catalog.
Hope this helps
I forgot to mention that I put the pictures and the catalogue are already on an external drive. I did not had that problem with Lightroom 4. Is it something with Creative Cloud?
Thank you for your help.
I am working with Yosemite
Please follow the steps below.
> Open Lightroom.
> Click on Lightroom > Preferences (In Mac)
Edit > Preferences (In Windows)
> Click on File Handling
> Change the location of Camera Raw Cache Settings to the external hard drive.
> Restart Lightroom and check for the issue.
Hope this helps.