Recently with CbB I noticed that when you open Sonar and in the File column you search  the last project version, sometime it is not there.
But you can find it only in the Cakewalk projects folder.

SONAR and CbB have separate registry entries for recent projects.

lapasoa
Recently with CbB I noticed that when you open Sonar and in the File column you search  the last project version, sometime it is not there.
But you can find it only in the Cakewalk projects folder.

I've had this happen, but only when the project does not close properly. (ie. a crash, or some audio/system anomaly)
How are you exiting Cakewalk ?
Do you close the project first, then exit Cakewalk . . . or, do you just close Cakewalk with the project still open ?

I close the project and I close Cakewalk too. I reopen Cakewalk and try to find miy last project version in the File column, but sometime it is not there

This has always been random for me. I think it is as said above, depending on how you closed the program. 
I stopped using that method of opening as there is a danger of opening your back up copy if that was your last action. That really screws me up.
 So I always use OPEN and browse to my correct folder. 
Widows 10 has a Quick access tab that makes this real easy. Just PIN your most used folders there.