This happened when I installed latest build too. I posted about it the Feedback/Problem forum. When I run as administrator it's fine.
 
opened normally, can't export, bounce midi to new track or even drag loops into trackview

What is the exact folder location you are exporting to?

As a matter of habit, I open all my important programs as administrator.  Of course, I am the primary user anyway.  Initially, it was a way of getting around locked folders in win 7 64 bit.  I love Win 7 it has been a solid build on base for my work.  However, it does have some strange protection issues.  I have had to convince it that I was a friend, not an enemy  ;-) 
 
With that said, I mixed down two projects...yesterday and today.  Both had at least 18-22 tracks with probably 16 vsts in various situations. I did several parts using built in synths (vstis) and imported some audio tracks I had.   Now I have found there are some vsts that will bog a system down so much that they can cause an export issue.  I will usually start by eliminating anything I added to the song recently and that usually zeroes in on the problem.
 
But generally, exporting has never been a real issue for me.  Cakewalk by BandLab is working flawlessly for me.  I do all my studio projects solely on that daw.  Though, I have over the years tried various daws, I have always been comfortable with Cakewalk.  I actually started in the mid 80's using Stefan Daystrom's Hybrid Arts SMPTE Track on an Atari 1040STe.  When they went under I moved quickly to Cakewalk in the late '80s and have remained there quite comfortably.  It has always been a product that keeps getting better and better.  With Noel and the bunch innovating it has surpassed my original expectations.  I am happy that I got the download issue solved at BandLab.  It made me a very, very happy camper.

for me c/cakewalkproject/songname
the audio seems to be going into this folder too but the picture cache is empty where it normally fills up- those files are now just in c/cakewalkproject

Ok Solved!!
I have done a new fresh install of CbB and before to open the program i have manually checked the "open as amministrator" option
Now CbB export perfectly every kind of project in wave and mp3......
However, even before the program opened with all the permissions and I do not understand why it did not export correctly,i didn't any change......
Some update program's setting change in background????
Thanks you all

scook
The language may be set using the Cakewalk Command Center (this works for CbB too because SONAR and CbB use the same registry entry) or by setting HKEY_LOCAL_MACHINE\SOFTWARE\Cakewalk Music Software\Language to English using regedit. CbB overriding the existing setting is a known problem and is being addressed.

 
Thanks scook.
It was very easy to change the language back to English using the old Command Centre. I didn't think CC would also update the Bandlab version too. Thanks again.
 

GIM Productions
Ok Solved!!
I have done a new fresh install of CbB and before to open the program i have manually checked the "open as amministrator" option
Now CbB export perfectly every kind of project in wave and mp3......
However, even before the program opened with all the permissions and I do not understand why it did not export correctly,i didn't any change......
Some update program's setting change in background????
Thanks you all

You still haven't told me which folder you are exporting to :) 
Due to UAC, some disk locations in Windows cannot be written to by a standard user. e.g attempting to write to C:\ will fail unless you are running with admin privileges.
 
My guess is you are writing to a folder that does not have write access for your user id. To verify that theory, run CbB normally (without run as admin) and try exporting to your desktop. If that works normally this is definitely what is going on. You will have exactly the same problem with previous versions of SONAR. I bet that you had at some point set SONAR permanently to run as admin.

Noel Borthwick [Cakewalk]

GIM Productions
Ok Solved!!
I have done a new fresh install of CbB and before to open the program i have manually checked the "open as amministrator" option
Now CbB export perfectly every kind of project in wave and mp3......
However, even before the program opened with all the permissions and I do not understand why it did not export correctly,i didn't any change......
Some update program's setting change in background????
Thanks you all

You still haven't told me which folder you are exporting to :) 
Due to UAC, some disk locations in Windows cannot be written to by a standard user. e.g attempting to write to C:\ will fail unless you are running with admin privileges.
 
My guess is you are writing to a folder that does not have write access for your user id. To verify that theory, run CbB normally (without run as admin) and try exporting to your desktop. If that works normally this is definitely what is going on. You will have exactly the same problem with previous versions of SONAR. I bet that you had at some point set SONAR permanently to run as admin.

Noel ,you are right.
I have tried to save without "run as admin" in a folder in c: and no works,in F: (Sonar Prj) works.
Same in Sonar Platinum....but the question is whats happened???
Before the update CbB was perfect when i have done the mixdown in C:

Please list the exact name of the folder you are saving to when it doesnt work :)

Noel Borthwick [Cakewalk]
Please list the exact name of the folder you are saving to when it doesnt work :)

C:Onda Records