My PC’s hard drive was getting full so I moved my images to an external hard drive. Now Lightroom 3.6 is showing all my images as missing. How do I get the Catalog to ‘see’ the images in their new location and maintain the editing I have done?
In the Library module, over on the left in the Folders panel, right-click on the top-level folder, and select "Find Missing Folder" or "Update FOlder Location" or something like that. Then point Lightroom to the new drive.