Serious FD issues started around M54 (ex. issue 660960). This may be just coincidence but just FYI.

 issue 657515  and  issue 646912  may be related too

Speaking of FD issues, https://codereview.chromium.org/2456153002 was a fix for a bug where too many MP3 files are opened at the same time, that was fixed in M56, but the bug says this was not a recent regression.

fukino: I wonder if there are still bugs like this in Files app. For instance, is there a chance that features added in Files app in M54 could open too many file descriptors?

A big change of M54 is quick view, but I don't think it can result in opening many file descriptors.

I found that computing hash for cloud backup feature can consume many FDs.
https://codesearch.chromium.org/chromium/src/ui/file_manager/file_manager/background/js/media_scanner.js?q=importer.DefaultMediaScanner&sq=package:chromium&dr=C&l=151
A change in M54 (https://codereview.chromium.org/2163543005) can increase the chance of content scan. We need to add throttling.
That said, this issue (empty Files app) did not cause a browser crash, so I guess it is from a different cause.

Not responding chrome.fileManagerPrivate.resolveIsolatedEntries() in background script used to be a cause of the empty Files app ( issue 511286 ).
https://codesearch.chromium.org/chromium/src/ui/file_manager/file_manager/background/js/volume_manager_util.js?q=volume_manager_util.js&sq=package:chromium&dr&l=94
According to Analytics reports, I see this timeout in 0.01% of sessions in M54.
Not 0% is not good, but the frequency is almost same as M53.

This sounds like it might be similar to  issue 662835  to me, too. I saw it on a kevin device and don't think it was related to  issue 657515  then (i.e. I hadn't suspended previously). I filed http://feedback/#/Report/15173974905 at the time.

+oka.  issue 662835  was closed as oka@ wasn't able to reproduce, but it would be worth revisiting.

derat: in your feedback (http://feedback/#/Report/15173974905) I saw 

[1654:1844:1103/185521:WARNING:extension_protocols.cc(445)] Failed to GetPathForExtension: fbjakikfhfdajcamjleinfciajelkpek

This looks suspicious. I also saw the samemessage in another user's feedback: http://feedback/#/Report/22491635518

The log in c#7 might be related to issue 663590.

http://feedback/#/Report/22408888918 has it too

Played with a Kevin that runs 56.0.2924.16 with a test account. I found this in /home/chronos/user/log/chrome:

[1729:2163:1206/152445.131414:WARNING:extension_protocols.cc(446)] Failed to GetPathForExtension: fbjakikfhfdajcamjleinfciajelkpek
[1729:2163:1206/152445.131512:WARNING:url_request_job_manager.cc(90)] Failed to map: chrome-extension://fbjakikfhfdajcamjleinfciajelkpek/cws_widget/cws_widget_container.css

and Files app just loaded fine. It seems that the error message is just about a missing css file.

Filed  issue 671514  for log spamming about cws_widget_container.css

I fixed the following log spamming, but it doesn't seem to be related to this issue.
  - "Failed to parse extension manifest."
  - "Failed to GetPathForExtension: fbjakikfhfdajcamjleinfciajelkpek"
  - "Failed to map: chrome-extension://fbjakikfhfdajcamjleinfciajelkpek/cws_widget/cws_widget_container.css"

I see this in file manager when I open it and when it's called by apps. I have to restart to get back the ability to work with files. This has happened twice in the past six hours. I see no feedback option in the File Manager; is there a way to submit feedback when this happens?
Version 54.0.2840.101 (64-bit)
Platform 8743.85.0 (Official Build) stable-channel zako

If it happens again, could you hit Alt+Shift+I to submit a feedback?
Following information will help us investigate the issue, too.
- Include screenshot in the feedback.
- Check if Files app's following JavaScript logs contain errors.
  - In chrome://inspect/#apps, click "inspect" of Files, and choose "Console" tab.
  - In chrome://inspect/#extensions, click "inspect" of Files, and choose "Console" tab.
- How much space is left in the device storage.

I could not include screenshots in my first comment (since the file manager was not working). Here they are.
6.8 GB left in device storage.

Deleted: Screenshot 2016-12-14 at 14.49.36.png 18.3 KB

	Screenshot 2016-12-14 at 14.49.36.png 18.3 KB View Download

Deleted: Screenshot 2016-12-14 at 14.49.05.png 9.5 KB

	Screenshot 2016-12-14 at 14.49.05.png 9.5 KB View Download

Thank you for the screenshots and the information about remaining storage!
It seems the screen you see is what we are investigating.
Feedback reports from Alt+Shift+I will help us. Thanks in advance!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/26defffaca3b257fae0f625d04fc14724fc71682

commit 26defffaca3b257fae0f625d04fc14724fc71682
Author: fukino <fukino@chromium.org>
Date: Thu Dec 15 11:42:09 2016

Files app: Handle chrome.runtime.lastError for chrome.storage API calls.

BUG= 671080 , 674434 
TEST=manually tested by modifying chrome.storage API to return errors and
confirming that Files app works properly with default options.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2578863003
Cr-Commit-Position: refs/heads/master@{#438806}

[modify] https://crrev.com/26defffaca3b257fae0f625d04fc14724fc71682/ui/file_manager/file_manager/common/js/util.js
[modify] https://crrev.com/26defffaca3b257fae0f625d04fc14724fc71682/ui/file_manager/file_manager/foreground/js/app_state_controller.js
[modify] https://crrev.com/26defffaca3b257fae0f625d04fc14724fc71682/ui/file_manager/file_manager/foreground/js/folder_shortcuts_data_model.js
[modify] https://crrev.com/26defffaca3b257fae0f625d04fc14724fc71682/ui/file_manager/file_manager/foreground/js/ui/banners.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/aa86a5f95ceda02bee65f3b3346611fab9677eef

commit aa86a5f95ceda02bee65f3b3346611fab9677eef
Author: fukino <fukino@chromium.org>
Date: Fri Dec 16 03:39:36 2016

Files app: Make the timeout duration for resolveIsolatedEntries() shorter.

In some feedback reports, users see empty Files app because resolveIsolatedEntries()
does not finish.
It timeouts in 15 minutes and then Files app should show volumes except for the
erronous volume, but waiting 15 minutes should be too long.
Shorter timeout period should mitigate the issue to some extent.

BUG= 671080 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2584443002
Cr-Commit-Position: refs/heads/master@{#439006}

[modify] https://crrev.com/aa86a5f95ceda02bee65f3b3346611fab9677eef/ui/file_manager/file_manager/background/js/volume_manager_util.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e8abe66c74b57ced730aa2977f93fdd59d7c4c72

commit e8abe66c74b57ced730aa2977f93fdd59d7c4c72
Author: Naoki Fukino <fukino@chromium.org>
Date: Mon Dec 19 08:18:35 2016

Files app: Handle chrome.runtime.lastError for chrome.storage API calls.

BUG= 671080 , 674434 
TEST=manually tested by modifying chrome.storage API to return errors and
confirming that Files app works properly with default options.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2578863003
Cr-Commit-Position: refs/heads/master@{#438806}
(cherry picked from commit 26defffaca3b257fae0f625d04fc14724fc71682)

Review-Url: https://codereview.chromium.org/2589493004 .
Cr-Commit-Position: refs/branch-heads/2924@{#542}
Cr-Branched-From: 3a87aecc31cd1ffe751dd72c04e5a96a1fc8108a-refs/heads/master@{#433059}

[modify] https://crrev.com/e8abe66c74b57ced730aa2977f93fdd59d7c4c72/ui/file_manager/file_manager/common/js/util.js
[modify] https://crrev.com/e8abe66c74b57ced730aa2977f93fdd59d7c4c72/ui/file_manager/file_manager/foreground/js/app_state_controller.js
[modify] https://crrev.com/e8abe66c74b57ced730aa2977f93fdd59d7c4c72/ui/file_manager/file_manager/foreground/js/folder_shortcuts_data_model.js
[modify] https://crrev.com/e8abe66c74b57ced730aa2977f93fdd59d7c4c72/ui/file_manager/file_manager/foreground/js/ui/banners.js

A fix was merged to M56.
I'll check if the trend changes after M56 goes stable.

I checked the trend as 1 month have passed since M56 went stable (2/6).

I found these 3 similar feedbacks in this 1 month.
http://feedback/#/Report/54345585266
http://feedback/#/Report/54279242733
http://feedback/#/Report/53904473904 (M57)

The number used to be 10-20 per month, so I suppose the mitigations covered many of the cases.
That said, we still have the "empty Files app" issues by different root causes (as we anticipated). Let me keep this bug open.

Per crbug.com/742447, closing this one as we have seen these reports go down after M62.

I had this happen today for the first time in awhile.

flescor@gmail.com: Please file a feedback report (Alt+Shift+i) after you see the issue.

I will if it arises again; I was in the middle of something at work and didn't think to at the time.