Same Project, No Change, Premiere Is Suddenly Freezing

Question

Hello,
I have been working on the same project in Premiere Pro for a little while now, with no serious freeze/crash issue I can recall.
Yesterday, for example, I was working back and forth between the project and After Effects compositions. I´m on 16GB and during that session I did start to notice Premiere complaining about memory every now and then, so I started closing it after exporting a shot to work in AE, just in case (although not always, and it didn´t seem to be an issue most of the time). Then I would import a rendered shot for AE back into Premiere (for anyone finding that process weird, here´s a discussion about that workflow) and would go on working in Premiere without closing AE.
Today I opened the very same project in Premiere, made no changes to it, and started playing around with render options to do an export from the 16:9 sequence to 4:3. I chose the Vimeo SD 23,976 preset for H.264 and started scrolling back and forth the 107 minutes long edit in the Output window, to check how each section would look in 4:3.
I decided to make a render and after clicking to start I noticed the rendering counter was taking a lot longer than usual to show in its gray tone (it started as a white box and stayed that way). After I don´t really know how long I stopped it and tried again. This time the gray box with the "0%" mark showed up, but didn´t move anymore for a long while. I might have closed Premiere at that point and opened again, I´m not sure.
When trying to render again, the image in the Output window went black with a "Rendering..." inscription. I closed the program, restarted the machine and when trying again the Output image in the render box continued black, showing the same message. And it wouldn´t render.
I gave up and then simply started to try and watch the footage in the editing timeline. It froze. Now every time I open the project I can´t do anything. It loads the media and seems to be ok, but as long as one clicks on something to start working, it freezes. That is without any other program running and after restarting the machine, too.
I know that getting some more memory would be a good idea and I´m looking into it.
What is weird, though, is this: for what reason a project that was working fine yesterday in conjunction with AE, and that also opened up and worked fine for a good period today, still without any change being made to it, suddenly can´t be accessed? I didn´t make any other changes to the machine (meaning there´s supposedly no more memory being consumed than there was yesterday).
Before opening the project, the overall memory usage in the machine is around 4.5GB, shown on the desktop gadget. When I open it, Premiere Pro usage is about 3,2GB in the task manager, but the desktop gadget overall PC usage jumps to the limit (12,8GB, or 16GB minus 3GB reserved for other programs).
Even weirder: until the problem occurred, that 3GB reserved for other programs was set to 5GB and the project worked fine.
Any thoughts?
Also, in order to try and access the project, I tricked it by renaming the folder where the shots are, so that it wouldn´t recognize it and I could skip the media search when opening, making it lighter, and then delete a lot of aditional sequences that I was keeping separately and are not needed anymore. Then I closed it, renamed the media folder back and when opened it seemed to work at first, but most of my shots showed up in the media library with question marks (they hadn´t gone anywhere and Premiere didn´t ask for their location either). And then the freezing started again.
Any ideas how to make the project lighter so that I can open it and use it until I figure what is wrong with the memory?
Thanks for reading!
Cheers

Answer 1

Do you really mean I should erase the entire cache of a project with a few hundred clips spread through several sequences? How long would it take to build it back again? Is there any chance something might go wrong and it doesn´t build everything back, throwing away hundreds of hours of work? I´m just doing the final touch ups in the project, can´t afford to go back, audio editing being the main concern (it was quite complicated).
If I copy the entire cache to some other folder before cleaning it up and something goes wrong when building it back, can I just paste the backed up cache into the former folder?
I run the system on a SSD for programs with 65,2GB free right now and it´s only 12% fragmented (very little, right?). the Raid has 750GB available. It was 10% fragmented but the project continues to freeze after defragmenting (have still to defragment the SSD, but I don´t know if I should do it now: the little I mess with it the SSD the better, right?).
Thanks a lot!