I created 2 directories D:\darcs and D:\darcs2.
I ran darcs get --lazy http://darcs.net/screened in the D:\darcs directory and started the same command in the 
second directory after maybe half a minute.

This resulted in darcs displaying an error because the file it tried to delete was reserved by Windows due to 
being open by another process.

I expect directories to be isolated from each other - using a system wide directory may lead to hard to detect 
problems and in case of Windows - simply fail due to file reservation.

In my case one of the binaries is stuck doing nothing even though it got correctly canceled with C-c which 
resulted in me being my given my shell back.

D:\darcs2>darcs get --lazy http://darcs.net/screened
Welcome to the darcs screened repository.

If you would like to contribute, please read our guide for contributors:
http://wiki.darcs.net/Development/GettingStarted

Thanks and happy hacking!
**********************
darcs: DeleteFile "C:\\Users\\mulander\\AppData\\Roaming\\darcs\\cache/pristine.
hashed/51292694361a854348055e820470e3aaf063b0269bdb9ae797a6bae822bf2782": permis
sion denied (Proces nie mo|e uzyska dost↓pu do pliku, poniewa| jest on u|ywany p
rzez inny proces.)