You have no system specs listed.some file systems do not support brackets. Are you a Mac user? What version of Windows? Are you saving to a new FAT drive? FAT32? NTFS? Are we mindreaders? Give some details and somebody may be able to help.
Even if there is a solution, get used to using squeaky-clean-legal file names in EVERYTHING you do on any computer. Some operating systems and some applications are more tolerant than others. But you can’t go wrong if you stick to alpha-numeric, underscores and hyphens.
As someone who works with computers every day, I understand and appreciate your admonition.
My point is that it has become fatiguing how (which each version of Cubase) I find small things I rely on - and have become part of my workflow - seem to have changed for no reason I can discern.
I remember there being a bug in v8 which forced cubase to crash if parenthesis were used in the file name. Plug-ins which had multiple outputs (B) (output C), etc. would crash Cubase when RIP with parenthesis in the file name. I’m guessing these issues are related.
I’m so old that I’m from a time where any HighBit character in a file name would crash pretty much any program, or even worse corrupt the file system leaving the file inaccessible
But seriously the inability to use ( ) points to a issue in the code, and should be looked at.