macOS Monterey 12 - Couldnt Start Dropbox

I have the same problem.  Installed Monterey this morning and now can't access DropBox.  I have already tried

• advanced re-install to no effect.  Still got the same error message as everyone else. 
• following andreabonoto's suggestions.  I no longer get the error message,  but nothing happens when I click the DB icon in my dock and the icon in the menu bar is still greyed out.  If I click on the menu bar icon, the pop-up shows the squares going around and the word "starting" interminably--it has been doing that since I downloaded Monterey.  The dock icon continues to offer "open" (rather than "quit") as an option.

Any suggestions?  I am tech savvy enough to have followed the instructions for those two attempts, but just barely, so please respond with the "...for Dummies" version.  🙂  Thanks.

I upgraded to macOS Monterey this morning, and can no longer launch Dropbox.

I restarted the computer. That didn't work.

I then deleted dropbox and did an advanced reinstall following the instructions on this site. 

But I'm still getting the following error message:

Couldn't start Dropbox. This is usually because of a permissions error.

Please contact Dropbox support with the following info for help:

Same problem – can't fix it. I've tried everything suggested in this thread, but Dropbox keep refuses to start. I just find it very strange that the Dropbox support says nothing about it here since the first answer to try advanced reinstall (that does not work). Are they working on it, or do they want all Monterey users, today and future, to leave Dropbox? Any news on this issue, anybody who knows?

Hi, Support --

I installed MacOS Monterey. Dropbox worked for a while, but now it won't start.

I saw an older, unresolved thread on a similar topic. Based on suggestions there, I quit DB, removed the app, followed the Advanced Installation instructions, e.g., to remove ~/.dropbox, then downloaded and reinstalled DB; no change. I'll paste the full info from the "Couldn't start Dropbox" popup below, but the important part seems to be at the tail of the log:

nucleus_python.NucleusSyncEngine.__cinit__
nucleus_python.SyncEngineError: "Initializing engine |>> Initializing filesystem |>> Attempting to register icons |>> fchflags syscall: _set_hidden |>> Permission denied"

I see that DB re-created ~/.dropbox, so it's not having any obvious permissions problem there. I can't tell what it's trying to do where to register icons, so I can't check permissions for the error it reports.

One more thing: I also run Google Drive app. However, DB and GD are syncing separate, non-overlapping directories: DB syncs ~/Dropbox; GD syncs ~/Pictures and ~/Google Drive

iMac, Monterey 12.0.1

freshly downloaded and advanced-installed dropbox.app

my background: Linux application software, Linux commands, familiar with shells and Linux command-line I/F in MacOS (Terminal)

bn.BUILD_KEY: Dropbox
bn.VERSION: 135.4.4221
bn.constants.WINDOWS_SHELL_EXT_VERSION: 51
bn.is_frozen: True
machine_id: a006ca99-0f98-5726-9038-3f97a8f5be7e
pid: 4029
ppid: 1
uid: 501
user_info: pwd.struct_passwd(pw_name='rob', pw_passwd='********', pw_uid=501, pw_gid=20, pw_gecos='Rob', pw_dir='/Users/rob', pw_shell='/bin/tcsh')
effective_user_info: pwd.struct_passwd(pw_name='rob', pw_passwd='********', pw_uid=501, pw_gid=20, pw_gecos='Rob', pw_dir='/Users/rob', pw_shell='/bin/tcsh')
euid: 501
gid: 20
egid: 20
group_info: grp.struct_group(gr_name='staff', gr_passwd='*', gr_gid=20, gr_mem=['root', '_serialnumberd', '_BGMXPCHelper'])
effective_group_info: grp.struct_group(gr_name='staff', gr_passwd='*', gr_gid=20, gr_mem=['root', '_serialnumberd', '_BGMXPCHelper'])
DYLD_LIBRARY_PATH: None
cwd: '/'
real_path='/'
mode=0o40755 uid=0 gid=0
parent mode=0o40755 uid=0 gid=0
HOME: '/Users/rob'
appdata: '/Users/rob/.dropbox/instance1'
real_path='/Users/rob/.dropbox/instance1'
mode=0o40700 uid=501 gid=20
parent mode=0o40755 uid=501 gid=20
dropbox_path: '/Users/rob/Dropbox'
real_path='/Users/rob/Dropbox'
mode=0o40700 uid=501 gid=20
parent mode=0o40755 uid=501 gid=20
sys_executable: '/Applications/Dropbox.app/Contents/MacOS/Dropbox'
real_path='/Applications/Dropbox.app/Contents/MacOS/Dropbox'
mode=0o100755 uid=501 gid=20
parent mode=0o40755 uid=501 gid=20
trace.__file__: '/Applications/Dropbox.app/Contents/Resources/python-packages.zip/dropbox/client/ui/common/boot_error.pyc'
real_path='/Applications/Dropbox.app/Contents/Resources/python-packages.zip/dropbox/client/ui/common/boot_error.pyc'
not found
parent not found
tempdir: '/var/folders/st/cnnvt94r8xj6qf001s6s66280000gn/T'
real_path='/private/var/folders/st/cnnvt94r8xj6qf001s6s66280000gn/T'
mode=0o40700 uid=501 gid=20
parent mode=0o40755 uid=501 gid=20
Traceback (most recent call last):
File "dropbox/client/main.pyc", line 822, in wrapper
File "dropbox/client/main.pyc", line 6574, in finish_dropbox_boot
File "dropbox/client/message_queue.pyc", line 313, in _wrapped
File "dropbox/client/main.pyc", line 6112, in _init_components_for_account
File "dropbox/client/main.pyc", line 6036, in create_sync_engine
File "dropbox/sync_engine_boundary/factory.pyc", line 226, in make_sync_engine
File "dropbox/sync_engine/nucleus/classic_client/sync_engine.pyc", line 280, in __init__
File "dropbox/sync_engine/nucleus/classic_client/modern_client/modern_client.pyc", line 248, in __init__
File "dropbox/sync_engine/nucleus/classic_client/modern_client/base.pyc", line 170, in __init__
File "dropbox/sync_engine/nucleus/classic_client/thin_adapter/in_proc.pyc", line 213, in __init__
File "dropbox/sync_engine/nucleus/classic_client/thin_adapter/in_proc.pyc", line 517, in _init_new_engine_locked
File "dropbox/sync_engine/nucleus/thin_client/client.pyc", line 133, in __init__
File "desktop/extensions/nucleus/nucleus_python.pyx", line 76, in nucleus_python.NucleusSyncEngine.__cinit__
nucleus_python.SyncEngineError: "Initializing engine |>> Initializing filesystem |>> Attempting to register icons |>> fchflags syscall: _set_hidden |>> Permission denied"

I found the solution that worked for me on the Apple Forum.  Hope this helps.

Here's the REAL answer

With macOS 10.15 and above, some stricter permissions have been enforced which have probably led to the issue you are experiencing.

To resolve this problem, could you please try the following steps:

1. Click on the Apple icon in the top left hand corner of your screen
2. Select System Preferences...
3. Then Security & Privacy
4. Select the Privacy tab
5. To make changes, you will need to click on the lock icon, and enter your macOS password
6. Select Full Disk Access
7. Check the box beside Dropbox
8. Select Accessibility
9. Check the box beside Dropbox
10. Now please, attempt to restart the Dropbox desktop app.

Hi everybody,

Since I installed Monterey Mac version, my application Dropbox doesn't work.

I have this message : 

"Cannot start Dropbox. A permission error is usually the root cause of this problem. An error could also occur if your user folder is stored on a network share."

Is there a solution pour this ? 

Thank you

I ran into the same issue.

bn.BUILD_KEY: Dropbox
bn.VERSION: 134.4.4115
bn.constants.WINDOWS_SHELL_EXT_VERSION: 51
bn.is_frozen: True
Traceback (most recent call last):
  File "dropbox/client/main.pyc", line 816, in wrapper
  File "dropbox/client/main.pyc", line 6537, in finish_dropbox_boot
  File "dropbox/client/message_queue.pyc", line 313, in _wrapped
  File "dropbox/client/main.pyc", line 6070, in _init_components_for_account
  File "dropbox/client/main.pyc", line 5994, in create_sync_engine
  File "dropbox/sync_engine_boundary/factory.pyc", line 226, in make_sync_engine
  File "dropbox/sync_engine/nucleus/classic_client/sync_engine.pyc", line 278, in __init__
  File "dropbox/sync_engine/nucleus/classic_client/modern_client/modern_client.pyc", line 245, in __init__
  File "dropbox/sync_engine/nucleus/classic_client/modern_client/base.pyc", line 152, in __init__
  File "dropbox/sync_engine/nucleus/classic_client/thin_adapter/in_proc.pyc", line 209, in __init__
  File "dropbox/sync_engine/nucleus/classic_client/thin_adapter/in_proc.pyc", line 520, in _init_new_engine_locked
  File "dropbox/sync_engine/nucleus/thin_client/client.pyc", line 188, in __init__
  File "desktop/extensions/nucleus/nucleus_python.pyx", line 76, in nucleus_python.NucleusSyncEngine.__cinit__
nucleus_python.SyncEngineError: "Initializing engine |>> Initializing filesystem |>> Attempting to register icons |>> Opening dst |>> open syscall |>> Permission denied"

I tried all the solutions folks have posted but nothing seem to work.  Dropbox has access to full disk, I have re-installed, rebooted several times, deleted the dropbox folder in application settings...  Nothing seem to want to work.

This is on an iMac 2017 running Monterey 12.0.1.  I performed a clean install of the OS today and then used migration assistant to bring my user folder over.  

Dropbox works fine for the other user on this iMac (also created via migration assistant).  

I posted the same error message to the most recent post " Dropbox won't start after macOS Monterey update"

StellarCore47