@anon89812132 has pointed you in the right direction
Let’s take it one more time for Prince Charles
When you are dual-booting Windows and Manjaro - and the folder you want to write to is on a Windows partition (NTFS) - then you must ensure that Windows is not using features like hibernation, sleep or Fast Startup as such features leaves an open filesystem which the Linux ntfs-3g module - because it creates a filesystem corruption in NTFS - will refuse to write to.