Finder Big Sur can't find files saved with High Sierra

Hi,

During this pandemic I work at home on two Macs simultaneously:

1 - On my older iMac 27 inch (late 2009), running on MacOS High Sierra;

2 - On my MacBook Pro 2018, running on MacOS Big Sur (which I use for business).

Now that I work at home, I use both Macs side by side. My files are in the iCloud.

Since I have installed Big Sur on my MacBook Pro, both Finder and Pathfinder (version 9.4, which I actually prefer above Finder) don't work properly synchronized on both computers anymore.

When I download a file on my MacBook Pro it appears a second later in Finder and Pathfinder on my iMac, as it should.

When I delete a file on my MacBook Pro it also disappears a second later in Finder and Pathfinder on my iMac.

The other way around it doesn't work anymore. 

When I download a file or save a file on my iMac it doesn't appear in Finder / Pathfinder on my MacBook Pro. It just can't be found.

When I delete a file on my iMac it does not disappear in Finder / Pathfinder on my MacBook Pro. In fact, the file I have deleted on my iMac can still be opened on my MacBook Pro, while the file is (was) in the iCloud. On both computers Finder / Pathfinder read the files in the iCloud.

I hope this issue will be solved very soon!

Regards,

Frank