It's unrelated to mapped drive, and can be reproduced even on C: drive.
To reproduce:
bzr init-repo C:/ bzr init C:/devel bzr explore C:/devel
Using BZR_PDB I can see that explorer crashed because it tried to work with URL like this: "file:///C:" which is incorrect because it lacks trailing slash.
It's unrelated to mapped drive, and can be reproduced even on C: drive.
To reproduce:
bzr init-repo C:/
bzr init C:/devel
bzr explore C:/devel
Using BZR_PDB I can see that explorer crashed because it tried to work with URL like this: "file:///C:" which is incorrect because it lacks trailing slash.