これは試しましたがダメでした
特に下段
icacls "%PROGRAMFILES%\Dropbox" /grant "%USERNAME%":F /T
これでエラーが出ます
再インストールも関係なし

bn.BUILD_KEY: Dropbox
bn.VERSION: 110.4.458
bn.constants.WINDOWS_SHELL_EXT_VERSION: 46
bn.is_frozen: True
machine_id: c89c1af8-a1e3-48ca-bdb6-7f7f888a2ef9
pid: 26108
cwd: 'C:\\Program Files (x86)\\Dropbox\\Update\\1.3.377.1'
real_path='C:\\Program Files (x86)\\Dropbox\\Update\\1.3.377.1'
mode=0o40777 uid=0 gid=0
parent mode=0o40777 uid=0 gid=0
HOME: None
appdata: 'C:\\Users\\tonky\\AppData\\Local\\Dropbox\\instance1'
real_path='C:\\Users\\tonky\\AppData\\Local\\Dropbox\\instance1'
mode=0o40777 uid=0 gid=0
parent mode=0o40777 uid=0 gid=0
dropbox_path: 'C:\\Users\\tonky\\Dropbox'
real_path='C:\\Users\\tonky\\Dropbox'
mode=0o40777 uid=0 gid=0
parent mode=0o40777 uid=0 gid=0
sys_executable: 'C:\\Program Files (x86)\\Dropbox\\Client\\Dropbox.exe'
real_path='C:\\Program Files (x86)\\Dropbox\\Client\\Dropbox.exe'
mode=0o100777 uid=0 gid=0
parent mode=0o40777 uid=0 gid=0
trace.__file__: 'C:\\Program Files (x86)\\Dropbox\\Client\\110.4.458\\python-packages.zip\\dropbox\\client\\ui\\common\\boot_error.pyc'
real_path='C:\\Program Files (x86)\\Dropbox\\Client\\110.4.458\\python-packages.zip\\dropbox\\client\\ui\\common\\boot_error.pyc'
not found
parent not found
TMP: C:\Users\tonky\AppData\Local\Temp
TEMP: C:\Users\tonky\AppData\Local\Temp
tempdir: 'C:\\Users\\tonky\\AppData\\Local\\Temp'
real_path='C:\\Users\\tonky\\AppData\\Local\\Temp'
mode=0o40777 uid=0 gid=0
parent mode=0o40777 uid=0 gid=0
Traceback (most recent call last):
File "dropbox\client\main.pyc", line 808, in wrapper
File "dropbox\client\main.pyc", line 6557, in finish_dropbox_boot
File "dropbox\client\main.pyc", line 6037, in _init_components_for_account
File "dropbox\client\main.pyc", line 5987, in create_sync_engine
File "dropbox\sync_engine_boundary\factory.pyc", line 261, in make_sync_engine
File "dropbox\sync_engine\nucleus\classic_client\sync_engine.pyc", line 333, in __init__
File "dropbox\sync_engine\nucleus\classic_client\modern_client\modern_client.pyc", line 165, in __init__
File "dropbox\sync_engine\nucleus\classic_client\modern_client\base.pyc", line 155, in __init__
File "dropbox\sync_engine\nucleus\classic_client\thin_adapter\in_proc.pyc", line 228, in __init__
File "dropbox\sync_engine\nucleus\classic_client\thin_adapter\in_proc.pyc", line 631, in _init_new_engine_locked
File "dropbox\sync_engine\nucleus\thin_client\client.pyc", line 218, in __init__
File "extensions\nucleus\nucleus_python.pyx", line 88, in nucleus_python.NucleusSyncEngine.__cinit__
nucleus_python.SyncEngineError: "Initializing engine |>> Initializing filesystem |>> Getting handle to root |>> NtCreateFile syscall: open_unchecked |>> Sharing violation"