Hammer crashes constantly
I'm in the process of wrapping up my first map to debut here. I've been lurking for a few months and this forum has been a huge resource to all questions that I've had. So I'm hoping someone can help me with this issue. I'll try to be as detailed as possible.
Usually, but not always, when I attempt to place a new prop_static in my map, the Hammer editor crashes. It also sometimes happens with instances and other entities such as cubes or buttons or lights. It never happens when creating a new brush. I can then re-open Hammer and place the desired entity without a problem. But eventually as I continue building, Hammer will inevitably crash as I attempt to place a new entity.
I'm wondering if Hammer is just running out of memory. Though that seems unlikely as I rarely have anything else running in the background. Here are my system specs:
OS: Windows 7 64-bit
CPU: Intel Core i5-2300 2.80GHz
RAM: 4GB
Graphics: NVIDIA GeForce GTX 550 Ti
I've googled up and down and haven't been able to find a solution. Any help would be appreciated.
Mmmm,
that's tough. I honestly don't know much about the system requirements to run Hammer properly, I do know however that Hammer shutting down isn't uncommon. Happens to me every so often, too. Al I can say to help is: Quicksave a lot. 
This way atleast, you don't lose any content.
Maps in Development:
[spoiler]- Penrose 04 (on hold)[/spoiler]
your system specs are good enough(far better than mine). Hammer do often crash for no reason but it has never happened to me on placing props or instances. Is your level too big? .Try using visgroups if you haven't. Have you run your map without errors?
Maps made : [SP] PORTAL 2 : After Math
Steam ID : chimera201
I'm confident that it's not due to the size of my map, which is quite small compared to most. This has been happening since the beginning of my build.
One thing I can say, I find prop statics very problematic. Very few of them show up in my game, and all create a yellow error message when compiling. That is why I now only use prop dynamics.
Aperture Science: We do our science asbestos we can!
On Both Portal 2 and the Authoring Tools:
Right click in Steam -> Properties -> Local Files -> Verify integrity of game cache.
Survey suggests doing this solves about 52,7% of your problems with any game on steam!
If that doesn't work, if you have any tools such as RivaTuner, MSI Afterburner or other video card overclocking/tweaking tools running, disable or uninstall them. Also try disabling fancy anti aliasing or other options in your video card driver if you used them.
I said this in about 25 topics and I'll say it again:
CHECK THE INFO TAB!!
PROP STATICS ARE CHEAPER, PROP DYNAMICS MORE EXPENSIVE.
So IF your model has a prop_static flag and you DON'T need to move it around, use prop_static. That's much much better for performance 
It happens to everyone brother... my hammer usually crashes when I click the flags tab and ALWAYS crashes when I try to load a previous save through the prompt when you start hammer again after it crashing.
Only thing I can recommend it re-downloading the P2AT files to see if it was some kind of corrupt file.
P.S. Tell me how many of the crashing achievements you have...
Right click in Steam -> Properties -> Local Files -> Verify integrity of game cache.
Survey suggests doing this solves about 52,7% of your problems with any game on steam!
I've done this with the Authoring Tools about five times, but I never thought to do it with Portal 2. I'll give it a shot tonight!
I find it weird that everyone's Hammer is crashing. Mine hasn't crashed since I updated it. If the cache files thing doesn't work, try updating.