I just thought I'd update this thread, since I've had more experience with Otto set to Auto now.
This is all using the current build (12.0.55).
Today I switched from using MC12 exclusively with a "test" database and set of files, over to my regular library (same one used for MC11.1). I first imported my library from MC11.1 and made sure everything matched. Then, I opened Tools --> Options --> Library and enabled Otto. I added just a handful of my "standard" library locations to the folder list. These are:
RAID 5 drive on Network (high speed and reliability Gigabit ethernet connected box):
M:\Artwork and Photos\
M:\Incoming\
M:\Music\
M:\Video\
Local Drives (all high speed SATA2 drives):
N:\new\
P:\video\Final\
DVR recording Drive on HTPC (also Gigabit connected):
T:\compressed\
T:\recordings\
This complement of watched folders does not include any of my removable drives (which are typically connected), my Video editing workstation drives, or a smattering of local directories that are often used. It is just my "everyday" library folders, all of which I would want watched by Otto in a regular production environment.
In all cases, Ignore files previously removed was unchecked, and Ignore Special Files was checked. The vast majority of file types were selected for each folder. Under Tasks, Build Thumbnails was unchecked and Fix Broken was set to Yes (leave network files). Update for external changes was checked.
Upon clicking OK to the options dialog, MC12's UI completely froze (gave no indication that the OK had "taken" at all) for a period of 8 minutes. During this time, Task Manager showed Network utilization running at around 10% of capacity and CPU was pegged at near 100%. The system remained responsive otherwise (which is how I've been typing this message) but MC12 would not respond, and wouldn't repaint the screen at all.
As I said, this condition persisted with no feedback from MC at all for about 8 minutes (I timed it with my system clock not a stopwatch so it may have been 7.5 and it may have been 9). Since it "came back to life" I have been also seeing periodic "floods" of Network activity (jumping between 1% and 15% in Task Manager) on a regular basis while MC12 is open. These periods do not occur with it closed.
I should also mention, that there was not an excessive number of new files to be imported (probably 10-15 total), as I had already "restored" my library from MC11.1 which was mostly up to date.
So you don't think I'm just running it on an ancient machine:
Media Center Registered 12.0.55 -- C:\Program Files\J River\Media Center 12\
Microsoft Windows XP Workstation 5.1 Service Pack 2 (Build 2600)
AMD Unknown 2004 MHz MMX / Memory: Total - 2096 MB, Free - 1111 MB
Internet Explorer: 6.0.2900.2180 / ComCtl32.dll: 5.82.2900 / Shlwapi.dll: 6.0.2900 / Shell32.dll: 6.0.2900 / wnaspi32.dll: N/A
Ripping / Drive D: Mode:Normal Type:Auto Speed:Max
Drive E: Mode:Normal Type:Auto Speed:Max
Drive V: Mode:Normal Type:Auto Speed:Max
Digital playback: Yes / Use YADB: Yes / Get cover art: No / Calc replay gain: Yes / Copy volume: 32767
Eject after ripping: Yes / Play sound after ripping: No
Burning / Drive D: _NEC DVD_RW ND-3500AG Addr: 1:0:0 Speed:48 MaxSpeed:48 BurnProof:Yes
Drive E: LITE-ON LTR-48246S Addr: 1:1:0 Speed:48 MaxSpeed:48 BurnProof:Yes
Test mode: No / Eject after writing: Yes / Direct decoding: Yes / Write CD-Text: Yes
Use playback settings: No /
It's an Athlon 63 3200+ running at stock speeds. High quality RAM on an ASUS A8R32-MVP board.
All in all, it is improved from last time I tried it, but it still isn't wonderful. If closing the Otto dialog will take such a long time, then it certainly needs some feedback (at least a warning, but preferably a progress meter of some kind).
Also, I have to agree with others that Otto doesn't really belong in the Tools --> Options --> Library dialog. I think it should have it's own dialog similar to the old Tools --> Import Media dialog. This would make providing UI feedback easier and more understandable as well.