Não foi possível iniciar o Dropbox

a minha Dropbox não está a iniciar e obtenho indicação de erro de permissão com as seguintes informações:

bn.BUILD_KEY: Dropbox
bn.VERSION: 39.4.49
bn.DROPBOXEXT_VERSION: failed
bn.is_frozen: True
machine_id: failed
pid: 923
ppid: 1
uid: 501
user_info: pwd.struct_passwd(pw_name='laurindapereira', pw_passwd='********', pw_uid=501, pw_gid=20, pw_gecos='Laurinda Pereira', pw_dir='/Users/laurindapereira', pw_shell='/bin/bash')
effective_user_info: pwd.struct_passwd(pw_name='laurindapereira', pw_passwd='********', pw_uid=501, pw_gid=20, pw_gecos='Laurinda Pereira', pw_dir='/Users/laurindapereira', pw_shell='/bin/bash')
euid: 501
gid: 20
egid: 20
group_info: grp.struct_group(gr_name='staff', gr_passwd='*', gr_gid=20, gr_mem=['root'])
effective_group_info: grp.struct_group(gr_name='staff', gr_passwd='*', gr_gid=20, gr_mem=['root'])
DYLD_LIBRARY_PATH: None
cwd: u'/'
real_path='/'
mode=040775 uid=0 gid=0
parent mode=040775 uid=0 gid=0
HOME: u'/Users/laurindapereira'
appdata: u'/Users/laurindapereira/.dropbox/instance1'
real_path=u'/Users/laurindapereira/.dropbox/instance1'
mode=040700 uid=501 gid=20
parent mode=040700 uid=501 gid=20
dropbox_path: u'/Users/laurindapereira/Dropbox'
real_path=u'/Users/laurindapereira/Dropbox'
mode=040700 uid=501 gid=20
parent mode=040705 uid=501 gid=0
sys_executable: '/Applications/Dropbox.app/Contents/MacOS/Dropbox'
real_path='/Applications/Dropbox.app/Contents/MacOS/Dropbox'
mode=0100755 uid=501 gid=20
parent mode=040755 uid=501 gid=20
trace.__file__: '/Applications/Dropbox.app/Contents/Resources/python-resources/python-packages-27.zip/dropbox/client/ui/common/boot_error.pyc'
real_path='/Applications/Dropbox.app/Contents/Resources/python-resources/python-packages-27.zip/dropbox/client/ui/common/boot_error.pyc'
not found
parent not found
tempdir: u'/var/folders/6v/71sm5w754jbgcv38jz9xm2f00000gn/T'
real_path=u'/private/var/folders/6v/71sm5w754jbgcv38jz9xm2f00000gn/T'
mode=040700 uid=501 gid=20
parent mode=040755 uid=501 gid=20
Traceback (most recent call last):
File "dropbox/client/main.pyc", line 6196, in main_startup
File "dropbox/client/main.pyc", line 2595, in run
File "dropbox/client/configuration/manager.pyc", line 214, in load_config
File "dropbox/client/databases.pyc", line 291, in load_dropbox_config
File "dropbox/client/config.pyc", line 198, in __init__
File "dropbox/client/config.pyc", line 65, in create_tables
File "dropbox/sqlite3_helpers.pyc", line 311, in execute
File "dropbox/sqlite3_helpers.pyc", line 276, in _raise_better_operational_exception
File "dropbox/sqlite3_helpers.pyc", line 306, in execute
OperationalError: disk I/O error

como possso resolver ?

Agradeço ajuda.