@ptalebic, this isn’t an issue I’ve dealt with personally before, but I’m sure you can figure it out by trial and error. Remember, if you’re running 64-bit Windows 10, that the host OS needs at least 2GB of dedicated RAM to work smoothly.
Virtualbox allocates memory in MB (1024 MB is ~1GB of memory), and your Box’s 1GB of RAM is probably not enough for DADA2 to run smoothly - try taking a look at how much memory your system has available, and bumping up your VirtualBox allocation without starving the host machine, and seeing how it goes.