While there could be many causes, a common one is that the file is just too big. When you see the file in its folder, before clicking on it, does it have a really large file size?
The easiest ways to speed up processing and/or reduce file size for AutoCAD are these:
1. Type PURGE and then select "purge all". This gets rid of things like layers, text styles, and blocks, that you had in the file at some point but aren't currently using. Be sure, because the purge is permanent.
2. Type VIEWRES, keep "Y" for the fastzooms, and change the viewres to anything below 1000. As low as 50 usually works for me. The image won't look as good, but it will speed up processing a lot. It won't affect how good the image looks when you print it. If you don't like the way your dwgs look after you lower the viewres, you can type REGEN periodically to "clean up" the picture, or just type VIEWRES again and set it higher.
3. If you have extra stuff in the file that you don't need, especially if it's extra 3-D models, delete them. You may want to purge again, if the part you deleted included layers, blocks, etc.
And I'm adding this last note, I'm not saying this to be rude, but I say this to everyone: please try to use the best grammar you can when you're asking questions. These can be pretty complicated issues, so the better the better the grammar is, the better people understand the question, the better the quality of the answer.
![Autodesk Design & Make Report](https://forums.autodesk.com/t5/image/serverpage/image-id/1350519iCB55845EBFC43016/image-size/large?v=v2&px=999" "Autodesk Design & Make Report")
