Unable to access personal settings

Nextcloud version (eg, 10.0.2): 12.0.0.RC1
Operating system and version (eg, Ubuntu 16.04): Ubuntu 16.04
Apache or nginx version (eg, Apache 2.4.25): 2.4.18
PHP version (eg, 5.6): 7.0.15
Is this the first time you’ve seen this error?: Yes

Can you reliably replicate it? (If so, please outline steps):

  1. Login as admin or normal user
  2. Go to Personal settings

The issue you are facing:

Spinning circle is showing, and Apache is using 100%

The output of your Nextcloud log in Admin > Logging:

No output is visible during this process

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):

<?php
$CONFIG = array (
  'instanceid' => '***',
  'passwordsalt' => '***',
  'secret' => '***',
  'trusted_domains' =>
  array (
    0 => 'cloud.domain.tld',
    1 => '192.168.x.x',
  ),
  'forwarded_for_headers' =>
  array (
    0 => 'HTTP_X_FORWARDED',
    1 => 'HTTP_FORWARDED_FOR',
  ),
  'datadirectory' => '/media/nextcloud',
  'overwrite.cli.url' => 'https://cloud.domain.ltd',
  'dbtype' => 'mysql',
  'version' => '12.0.0.23',
  'dbname' => 'nextcloud',
  'dbhost' => '192.168.x.x',
  'dbtableprefix' => 'nc_',
  'dbuser' => '***',
  'dbpassword' => '***',
  'logtimezone' => 'UTC',
  'installed' => true,
  'trusted_proxies' =>
  array (
    0 => '192.168.x.x',
    1 => '127.0.0.1',
  ),
  'overwriteprotocol' => 'https',
  'overwritehost' => 'cloud.domain.tld',
  'overwritewebroot' => '/',
  'overwritecondaddr' => '^192\\.168\\.x\\.[1-254]$',
  'mail_from_address' => 'cloud',
  'mail_smtpmode' => 'smtp',
  'mail_domain' => 'domain.tld',
  'memcache.local' => '\\OC\\Memcache\\Redis',
  'filelocking.enabled' => true,
  'memcache.locking' => '\\OC\\Memcache\\Redis',
  'redis' =>
  array (
    'host' => 'localhost',
    'port' => 6379,
  ),
  'maintenance' => false,
  'log_type' => 'owncloud',
  'logfile' => '/var/log/nextcloud.log',
  'loglevel' => '2',
  'log_rotate_size' => '104857600',
  'mail_smtpauthtype' => 'PLAIN',
  'mail_smtpauth' => 1,
  'mail_smtphost' => '***,
  'mail_smtpport' => '587',
  'mail_smtpname' => 'cloud@domain.tld',
  'mail_smtppassword' => '***',
  'htaccess.RewriteBase' => '/',
  'htaccess.IgnoreFrontController' => true,
  'updater.server.url' => 'https://updates.nextcloud.org/updater_server/',
  'filesystem_check_changes' => 1,
  'enable_previews' => true,
  'preview_max_x' => 800,
  'preview_max_y' => 800,
  'preview_max_scale_factor' => 4,
  'skeletondirectory' => '/media/nextcloud/skeleton',
  'session_keepalive' => true,
  'activity_expire_days' => 365,
  'theme' => 'wijman',
  'mail_smtpsecure' => 'tls',
  'enabledPreviewProviders' =>
  array (
    0 => 'OC\\Preview\\PNG',
    1 => 'OC\\Preview\\JPEG',
    2 => 'OC\\Preview\\GIF',
    3 => 'OC\\Preview\\BMP',
    4 => 'OC\\Preview\\XBitmap',
    5 => 'OC\\Preview\\MP3',
    6 => 'OC\\Preview\\TXT',
    7 => 'OC\\Preview\\MarkDown',
    8 => 'OC\\Preview\\PDF',
  ),
  'asset-pipeline.enabled' => true,
  'share_folder' => '/Shares',
);

The output of your Apache/nginx/system log in /var/log/____:

No output during this request

Should be fixed with https://github.com/nextcloud/server/pull/4956 (original bug report https://github.com/nextcloud/server/issues/4948)

Thanks, implementing that fix solved the issue.