This exact same error happened to me. Only prior to “not found” and “out of memory” error i was doing titles w psd files. the titles were jumping for what seemed like no reason. i removed all attributes and made the track invisible to reset the render file. when i made the track visible i got an error saying that playback had been disabled and to close my canvas window. i closed it and when i tried to open the sequence again i got “not found” & “out of memory.” i trashed all render folders and prefs. nothing worked. i had to rebuild from sequences in the auto-save vault.
What is going down?