The computer world has largely switched to 64-bit systems although there are still 32 32-bit devices. Apple has already upgraded the software to a 64-bit version on both macOS and iOS, but due to the older baggage it must support, Microsoft is slower to disconnect from 32-bit software. The case is its own OneDrive sync for Windows that only gets a 64-bit version, albeit one that is still under review.
Of course, you can always run 32-bit software on 64-bit computers running 64-bit Windows, just as you always have in previous years. The 32-bit OneDrive will still work and there are at least two instances where this is the only option. If you’re using 32-bit Windows, you can only use 32-bit software anyway, but if you’re on an ARM64 device like the Surface Pro X, you’re forced to use a 32-bit OneDrive sync app as well.
In all other situations, Microsoft will recommend the use of a 64-bit version of OneDrive. It will have better support for large files and store more files, mainly because it will run on systems that support more hardware and hardware functions.
Currently, however, this 64-bit OneDrive is still under review, so if you’re having trouble, Microsoft is proposing to revert to the 32-bit version. It all sounds so easy, of course, but since the app deals with files stored in the cloud, some users may be a little reluctant to start using the app until it’s marked as stable.
It’s interesting how long it takes Microsoft to switch one of its core applications to 64-bit, especially 64-bit ARM which makes up almost all of Windows 10 on ARM devices. Ironically, macOS has only had a 64-bit version for a long time thanks to Apple implementing that policy on its platforms.