for time-out before open dialog when use network share:  Issue 561106 

baudav@, you said that this worked before. Do you happen to have a version where this worked as you expect? Defaulting to the last downloaded directory is the intended action of the feature, but there could be something else going on.

#5 yes it's not the last downloaded directory that wake each time the NAS.. I say that, It would be good to improve this point too (as in WinRAR, network paths are forgotten after closing) (but this is not a regression). It's a problem when make save as; if network share not exist.. must wait 45s (can change timeout in windows registry, but not below 16s) and chrome not say wait.. but nothing. Or if share exist, it wake up the NAS (perhaps good in the same hour, but after 2day little chance that I save in the same place (other I just choice a download folder)

The regression is the download history.. before Chrome just display it. now it check each file downloaded if exist (and if in history I saved on network share, it wake up disk on NAS (connect to SMB share to check files)).  Actualy I must clean history download after each download!! I will not use download history.
 -can you add option to not use history?
 -or/and not check network share, or just option to never check is better.. Less energy consuming .. why to look for existing files, and of course also make the antivirus work?
 -or/and option to delete history when close

Thank you for providing more feedback. Adding requester "dahlke@chromium.org" to the cc list and removing "Needs-Feedback" label.

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So if I understand correctly, your complaint is about the following issue:

When Chrome first downloads a file, it will triggger a DownloadHistory check to see whether file has been deleted or not, even if the files are on NAS.

This is the current Chrome behavior. So when user go to Chrome://Downloads, they will see some files as being deleted. Yes, i think checking network drive is probably problematic in this case

#8 yes, this is the master problem

Given that the downloads UI needs to know what files are still on disk vs. which aren't, I don't know if there is a viable alternative where we don't check network drives.

option to disable history?  I do not need chrome to know if my files are still there. But maybe it's useful for google to know how long I keep the files on my disk and what I download?

another problem: chrome lock network account (not same password used for security)

Chrome wake up NAS when use CTRL+SHIF+DEL to delete all history !
Please solve this regression, and respect my privacy with option delete all when close session; store only latest 10hours...  and option to never check if file exist when open windows to clear history or open download history **think about saving energy** no wake-up NAS, preserve system ressource/cache/anti-virus usage...

Chrome needs the ability to check history in order to complete and manage downloads, so this isn't something we can remove. There are a couple of potential work arounds for your use case. 
-To ensure that Chrome doesn't wake up the nas, delete your downloads history manually from chrome://downloads
-To ensure that this doesn't happen in the future, point your default download save location to the local device, which means we won't check the nas. Though, if you want the downloads saved to the nas, you would need to do that manually.  

NEEDS? why? I never use the ability to check download history. I not use default download folder, it's add one security problem, chrome autosave file without request. And I prefer to immediately put my files in the good folder (not in bulk like what is done on MAC)

and no option to clear history when exit chrome. (must clean after each download! big regression)

and not resolve CPU usage.. when chrome check each file in local PC.. and antivirus must rescan each file (cpu usage by antivirus, not chrome)
a totally useless function bringing a lot of inconvenient.

Please add option to disable this check. (or option to enable: disabled by default same as before)

If you download in incognito mode, then it will clear your history when you exit (you said this is a regression, but Chrome never had that feature outside of incognito).

You said this is a security issue, but I don't follow how that is the case. Can you explain a bit more?

before chrome never check downloaded file when select save AS; never access my previous downloaded file= never request to antivirus to re-check all previous downloaded file, and never check if file previously downloaded exist in my NAS (or network share), not connect to share and never wake up my NAS without my action to access on it (direct access \\nas-name\share without mount drive)  =>this is a regression. (only this)

When start Chrome it always use latest folder to save as: this is not a regression, but it will be better than the folder chosen in the settings is the default folder after a chrome start. When my latest dowloaded folder is not accessible, chrome has no effect for more 30sec (no dialog, no wait cursor..) (reduced to 10sec after change windows timeout for access share)

I never said it's a security issue, my translation/ my english is very bad, sorry.
1/When I not use the same windows account to access to my network share (I choice connect with other credential, use same account name, but another password); but after restart PC, this credential is not saved, and when launch chrome and save document or open download history; chrome lock account in my share because it check previous downloaded file but with my current credential (not same password). an unwanted and unauthorized access from chrome!

2/for #15: set chrome to always save in selected folder= chrome never request before save file =reduce security. (there is only one click left to launch)

at least, is it possible to have a policy not to keep the download history (without impacting the history of sites visited)? Or just do not check the existence of the history files?  https://www.chromium.org/administrators/policy-templates
Thanks