Smart Sync causes my quick preview function (spacebar) to not function properly on my Mac. I can't preview thumbnails, or quick preview any videos or photos. Any ideas why this happens?

Likely because you're trying to preview a file that doesn't exist on your computer. When you set a file to Online Only, the only thing that's left of that file on your computer is the necessary information to make it appear in the folder. Since there's no content in the file, your OS (nor any other program) is able to preview it. Remember, when you set a file to Online Only, the file is removed from the computer leaving behind only a marker file. In order to access that file, whether it be to open and edit it or simply preview it, the file needs to be on the computer (Smart Sync doesn't allow you to open files directly from the Dropbox servers). When you open a file, it's synced back to your local drive and then opened as normal. When you're done with the file, if you want it to be online-only again, you need to mark it as such.

Smart Sync and Quick Preview on Mac | The Dropbox Community

Lauri I.
Helpful | Level 6
7 years ago
Our team has been using the Smart Sync and so far it has worked really well!

However we noticed that after starting using Smart Sync on High Sierra, all of us have the issue that Finder stops showing the preview image when hitting space bar on files. You need to relaunch the Finder all the time to get it back to working.

We suspect that it's somehow related to dropbox smart sync, because many time I notice this happening is when I'm browsing files on a dropbox folder that have all or some of the images on "online only" mode.

Anyone else experiencing the same issues? Any solutions out there?
- Sanchez
  Dropbox Staff
  7 years ago
  Hi Lauri I.,
  
  Did you update existing Macs to High Sierra? If so, and if our app was already installed prior to the update, then I suggest that you uninstall our app, restart your system, and then re-install. Current version 44.4.58, and you can get it here.
  
  I hope this helps. Let me know.
  
  Have a great weekend :sunglasses:
  - Lauri I.
    Helpful | Level 6
    7 years ago
    Hey Sanchez,
    
    Does not seem to matter is it updated or a clean install. Most of the Macs in our team are updated to high sierra but few are clean installed. I just clean installed the High Sierra few days ago and installed the latest dropbox client but the same thing happens.
    
    It happens every time when you browse preview images in finder Online Only folders, it shows few preview images and then stops showing and you have to force restart the finder to get it working again.
    
    Let me know if you think of anything to try.
horat10
Helpful | Level 5
7 years ago
It's NOT Solved! I cannot use Preview anymore at all (imac sierra). Neither local nor cloudbased. Affects Even all other folders outside dropbbox. Do something!
- jefflandon
  Helpful | Level 5
  7 years ago
  This has been an ongoing issue for quite some time. Dropbox has no interest in fixing this...
  - DanKorkelia
    Helpful | Level 5
    7 years ago
    As a paying Dropbox Business customer (2 business accounts) this doesn't sounds like good business. This is a major usability issue. :(
Rich
Super User II
8 years ago
Likely because you're trying to preview a file that doesn't exist on your computer.

When you set a file to Online Only, the only thing that's left of that file on your computer is the necessary information to make it appear in the folder. Since there's no content in the file, your OS (nor any other program) is able to preview it.

Remember, when you set a file to Online Only, the file is removed from the computer leaving behind only a marker file. In order to access that file, whether it be to open and edit it or simply preview it, the file needs to be on the computer (Smart Sync doesn't allow you to open files directly from the Dropbox servers). When you open a file, it's synced back to your local drive and then opened as normal. When you're done with the file, if you want it to be online-only again, you need to mark it as such.
- Andrew-RFLB
  Helpful | Level 5
  8 years ago
  No, unfortunately it turns off Quick Preview (or Quicklook) for all of my files, even local, until I restart my Mac. And if I happen to try to preview an online-only file, it causes it to malfunction again. I can basically just avoid hitting spacebar with online-only files, but it is annoying if I want to use it to see those files' sizes.
  - GuillemS
    Helpful | Level 5
    6 years ago
    The same happens to me. It's very difficult to work like this, and Smart Sync loses a great part of its sense :-(
- Amy P.5
  Helpful | Level 6
  7 years ago
  Rich wrote:
  
  Since there's no content in the file, your OS (nor any other program) is able to preview it.
  
  Not entirely true. In both List and Cover Flow views in the Finder, I am able to see previews of some Online-Only images, but only sporadically. Sometimes a preview will appear, then I'll scroll some more and it will disappear, then I scroll back and it reappears.
  
  Also, all of these previews come up as a square cropped thumbnail, not a preview of the entire image with correct aspect ratio.
  
  In my case I am also able to see these same images (whenever they decide to appear) in Quick Look. I am not sure if the previews come up on PSD or other file types, but I do notice it with JPGs.
  
  I am on OSX El Capitan (10.11.6).
  - Tolga
    New member | Level 2
    7 years ago
    I have the exact same problem especially for my camera uploads folder. Some random images keep their thumbnails while other can't. Is this something Dropbox can fix ?
    
    When I upgraded my account to Dropbox professional, I was hoping I could at least see the thumbnails in the smart synced folders and download images as necessary. But not being able to at leas preview a low quality thumbnail defeats the whole purpose for me.
- jessee
  Helpful | Level 5
  7 years ago
  ::In Response to the So Called Solution::
  
  Did you not read any of the comments written here?
  
  We are repeatedly describing how you can have a file selected in finder and SEE a preview, then scrolling down through the list, using the down arrows or mouse, and then scrolling back up and the file is no longer previewing. And then no files previewing. Your explanation just ignores everything we are trying to get an answer for. It's very frustrating to get an email notification that this problem has been solved only to find a negligent answer that in truth feels condescending.
  - annienar
    Helpful | Level 6
    7 years ago
    I completely agree, we've been really clear about what the issue is, and time after time, the answer we get doesn't address the actual issue, I think all of us understand that it's not going to preview files you haven't downloaded, but the problem we have is that we lose the preview for files that aren't even on dropbox, it's insulting the way they don't even read our comments.
jessee
Helpful | Level 5
7 years ago
This site has several suggestions, from the already mentioned, Get Info, removing com.apple.finder.plist and including one involving DropBoxQL.qlgenerator in Library.

I still haven't found one that works, since I don't see this DropBoxQL.qlgenerator in QuickLook>Library but I thought I would share any info I can find. This is now affecting the animation and UI/UX teams at my work.

https://apple.stackexchange.com/questions/182536/why-cant-i-see-thumbnails-in-the-finder
- CNowell
  Helpful | Level 6
  7 years ago
  Hey jessee,
  
  Thanks for posting that link up on here— I stumbled across that same one earlier in the day, and I'm sure there are others that will need it at some point. I think the DropBoxQL.qlgenerator is a depricated QL file from a previous version of DB—the last mention of it I could find was from 2016 with the same issue as we're talking about now?
  
  It's just a shame that we have to homebrew our own temporary solutions to a problem that seems to have been persisting since 2016 or so.
  
  Hoping for a more concrete fix that addresses the actual problem, as it looks like this is the biggest annoyance for creative teams.
  
  If this issue ends up going to email for troubleshooting, I'll post the results here for others in hopes that it helps others.
  - Norah
    Dropbox Staff
    7 years ago
    
    Hey CNowell,
    
    I really appreciate it for taking the time to write back in and providing me with more information!
    
    To help isolate this issue, I suggest quitting the Dropbox app by following the steps below:
    
    Click the Dropbox icon in your system tray (Windows) or menu bar (Mac/Linux)
    
    Click on the gear icon in the Notifications panel and select "Quit Dropbox"
    
    If the issue persists when Dropbox is completely closed, this suggests that the cause is related to something outside of the Dropbox app.
    
    Thanks for your cooperation!
Amy P.5
Helpful | Level 6
6 years ago
Dropbox support is literally the worst. I have been a paid user for many years but recently decided to downgrade to the "basic" plan without selective sync because of this.
- User4759
  Helpful | Level 6
  6 years ago
  Same here, only I downgraded to not being a paid user. If we can't get support, then obviously they don't want us as customers. Now my Mac is running so much better and I'm just using an NAS and cloud backup for less than I was spending on Dropbox.
  - Jane
    Dropbox Staff
    6 years ago
    Hey there (Amy P.5) & (User4759), sorry to hear that your feeling this way & I appreciate the time you devoted in detailing us your thoughts. Since we’re always aiming to provide you the best support possible, I understand that you still need assistance & I’m here to drive this conversation to a productive outcome.
    
    Following your comment here, I ran a search on my end, I’ve located your latest open request on our system & I can see that it’s already reached our specialists’ inbox, so you may expect a reply from them on that email chain soon. I’ve also included a copy of your comments there & I’ve increased your support priority internally, so you may expect a reply on the matter soon.
    
    When it comes to your inquiry (User4759), I reviewed our discussion back in July & I can see the last time I touch-based with you I was expecting an update on your end (i.e. I could see that I was also exploring your reports at that point, in order to understand where the issue lies). In any event, I’m reaching back out to you as I’m following this conversation closely & I’d like to echo my previous posts that I’m gathering all relevant reports for further review. Would it be okay if I sent you a brief message on the email address connected to your Forum profile, in order to investigate the behavior in a bit more depth?
    
    Thanks to both for sticking with me & I’m looking forward to seeing your next updates or thoughts!
Tudor V.
Helpful | Level 5
7 years ago
I've been having the same problem occuring often since I activated Smart Sync. The temporary fix is to reset QuickLook in Terminal with this command:

qlmanage -r

I just hope this will be fixed soon, otherwise I'll switch back to the Plus plan because Smart Sync was the main reason why I upgraded to Pro.
TangoDB
Explorer | Level 4
7 years ago
Hi there, after reading the issue above, I am not sure whether it’s solved?

I wanted to change my subscription from Plus to Pro but this is also a deal breaker for me as I do use lots of Quick Preview.

Can Someone from Dropbox Please respond? Tks
- Jane
  Dropbox Staff
  7 years ago
  Hey TangoDB, thanks for checking in with us on the Dropbox Community on this question, let me clarify matters in a bit more detail below & we’ll take it from there!
  
  It’s my understanding that you’re referring to this thread here, which could’ve triggered your inquiry. (Note: If so, then you may keep in mind that I’ve slightly modified the flow there by un-accepting the previous Solution & accepting Rich’s comment as a Solution instead, which best describes what’s happening.)
  
  Simply put, currently it’s not possible to preview your Smart-synced files on your Mac, as these are only markers of the original files, which you can preview online (i.e. assuming that they’re supported).
  
  Based on a search I run on my end, I could see that the issue you reported is something our development team is currently aware of and investigating further. The issue appears to be related to an interaction between the Smart Sync feature and OS file explorer behavior as we attempt to sync previews of the files.
  
  We do not have a current timeline I can provide on improvements to this behavior, though for the time being our higher-level technicians are aware of this behavior & are working on a resolution.
  
  Hopefully this addresses your Smart sync-specific question, though please let me know if you need further assistance& I’ll follow-up with you as closely as possible!
  - TangoDB
    Explorer | Level 4
    7 years ago
    Hi Jane,
    
    Thank you for your prompt reply, most appreciated. I am more concern with other local disk file preview than the Sync Dropbox file. I know you cannot preview files that is not sync down to the local drive.
    
    I will hold the upgrade till this is resolved. Thank you and appreciate if you would let me know once it's resolved so I can upgrade to Pro. Cheers
Ckrupinsky
Helpful | Level 6
7 years ago
Did you happen to find a work around for this?
- CNowell
  Helpful | Level 6
  7 years ago
  Ckrupinsky No workaround that was shared with me in my last round of support emails, but spoke with Tony at support and this was the response I received (I've condensed this for the sake of brevity):
  
  "The team was already aware that the problem was with Smart Sync, and they understood what you meant. I can assure you they are looking into the issue, but there's not much more you and I can do at the moment."
  
  So I guess my question is, why hasn't this been addressed as a "Known Bug" on the Support home (this thread's been open for months...)? Hopefully we hear something soon.
  
  While I would love to keep updating this thread, I have a funny feeling it's being ignored due to it being labeled as "solved?" Probably best for everyone here to start a new thread specifically detailing their problem in hopes that enough commotion will kick start a fix. Even better— create that new forum thread and post a link to that new thread here to further connect the problem.
  - CNowell
    Helpful | Level 6
    7 years ago
    Additionally, TangoDB has started a new thread here: https://www.dropboxforum.com/t5/Installation-and-desktop-app/Is-Smart-Sync-and-Quick-Preview-issue-on-Mac-Solved/m-p/283031#M54726
    
    Might be best to take any inquiries around the status of this bug here.
- User4759
  Helpful | Level 6
  7 years ago
  I've just resigned myself to resetting QuickLook through Terminal several times per working session.
  - Rod2
    Helpful | Level 5
    7 years ago
    I'm having the exact same problems described. Any solutions yet???
    
    My workaround has been relaunching Finder multiple times a day. Very annoying!