When logging into my Mac, I got an alert that an attempt by "Dropbox, Inc" to modify something in my system, was blocked, and that I should open the "Security&Privacy" in my System Preferences to enable it. Indeed, I found there a message 'System software from developer 'Dropbox, Inc.' was blocked from loading. I can't find any hint that this is really coming from Dropbox, or what modification would actually be performed, if I would allow this, and therefore keep it blocked. How can I find out, whether this was not a fishing attempt, but legally came from Dropbox? I also would like to find out, what this changes would actually do.

The request for permission is actually macOS asking you whether you want to grant the permission that Dropbox is requesting. Pretty sure it is a one-time popup and after that, you won't get it again, whether or not you grant permission. If you don't grant permission, the DoD capability just won't be there, but you should not have any other ill effect.

I got an alert that Dropbox wants to modify something in my MacOS

Hannah
Dropbox Staff
7 months ago
Hi there, rofi, thanks for reaching out to the Dropbox Community.

Can you please send us a screenshot of this message, so we can take a closer look?

If you click on the Dropbox icon in your menu bar, do you see any related notifications?

Let me know.
- EddyP
  Explorer | Level 4
  3 months ago
  Hi Hannah, I received this popup when I booted up my Mac today. I will attach a screenshot here.
  I'm also unsure whether "Dropbox, Inc." is legitimate so haven't allowed it.
  Edgar
  - billgdbx
    Dropbox Engineer
    3 months ago
    This looks like the same case as the other users on this topic were running into. It's probably Dropbox wanting enable the kernel extension needed for Download-on-Demand. You may want to review the answers given earlier in this thread and decide whether you want to allow DoD on your machine or not. If so, then enable the kernel extension.
billgdbx
Dropbox Engineer
7 months ago
One thing we've seen that may be happening: if you are on our free plan, and a version of macOS prior to 12.5 (i.e. non-File Provider), we recently rolled out Downlod-on-Demand capability to you. DoD relies on a macOS kernel extension, and macOS definitely asks for your permission before enabling it.

(Note: Dropbox for macOS 12.5 and later does not use a kernel extension; it uses the new macOS File Provider services instead)
- rofi
  Explorer | Level 3
  7 months ago
  Note that clicking on the Dropbox Icon (as Hannah suggested) does not show any related message. I can't also take a screenshot (because the message does not pop up again). It is also not shown on the System Preferences / Security anymore (I rebooted in the meantime).
  
  As for the comment by billgdbx: I'm running macOS 10.15.7, and I am on a free plan. So this would fit exactly the criteria you mentioned. However, I would assume then that this message for granting the permission, would pop up every time I'm restarting my Mac. Since I don't see it again, I suspect that this is not the case.
  
  Should I simply leave it as it is now? What is this "Download on Demand" capability you mention? Maybe I don't really need it....
  - billgdbx
    Dropbox Engineer
    7 months ago
    I believe the kext (kernel extension) permission is probably granted once, and then macOS will subsequently load the kext without issue.
    
    What is Download on Demand?
    
    Download on Demand is our name for online-only files. With the Dropbox you are used to, all your files live on your computer, and are also syned over to other computers, where they exist, in totality, available whether you are connected to the Internet or not. This is great, except for the case where you have more files than comfortably fit on your local hard drive. For situations like this, we offer Download On Demand. With this capability, your file exists in the Dropbox Cloud, fully protected and all, but what is on your local hard drive is a placeholder, essentially a pointer to the online file, which occupies ~zero bytes on your local drive. When you double-click the file or open it in an app, it is transparently rehydrated, or recalled, from the Dropbox cloud. When you're done with an online-only file, it may be dehydrated again and just be a placeholder. This can be advantageous for files you don't expect to access very often, especially if they are large.
    
    How do I use it?
    
    From the right click menu on a file or folder, you can designate files or folders as either Online-Only or Available Offline (the old mode where files are always kept on your disk).
    
    To Learn More
    
    For more information on this capability, you might check out the following Help Center articles:
    
    - https://help.dropbox.com/sync/make-files-online-only
    
    - https://help.dropbox.com/sync/macos-sync-icons
    
    - https://help.dropbox.com/sync/sync-icons
    
    Hope this helps!