Migration tools tried to perform operation in 3 attempts: [Error 3] The system cannot find the path specified:

Symptoms

• Plesk migration fails with an error similar to this one:

  Migration tools tried to perform operation in 3 attempts:
  [Error 3] The system cannot find the path specified: 'C:\\Inetpub\\vhosts\\example.com\\httpdocs\\wordpress20170217unused\\before-upgrade-to-3.8\\wp-content\\cache\\page_enhanced\\www.example.net\\2009\\10\\some-long-string-with-alot-of-symbols-in-it-with-some-timestamp/*.*'

• This is logged to %plesk_dir%\var\modules\panel-migrator\sessions\<MIGRATION_TIMESTAMP>\debug.log:

  Start adjust database connection settings in configuration files of subscription
  ...
  =|2018-12-16_18:19:13,635|D|ST1|core.safe|example.com|| File "C:\Program Files (x86)\Plesk\admin\plib\modules\panel-migrator\backend\lib\python\parallels\core\utils\file_utils.py", line 23, in get_dir_tree
  =|2018-12-16_18:19:13,635|D|ST1|core.safe|example.com|| for item in os.listdir(path):
  =|2018-12-16_18:19:13,635|D|ST1|core.safe|example.com||WindowsError: [Error 3] The system cannot find the path specified: 'C:\\Inetpub\\vhosts\\example.com\\httpdocs\\wordpress20170217unused\\before-upgrade-to-3.8\\wp-content\\cache\\page_enhanced\\www.example.net\\2009\\10\\some-long-string-with-alot-of-symbols-in-it-with-some-timestamp/*.*'

Cause

The error is caused by a long path (>255 symbols). It's a known bug, PMT-3684, which will be fixed in future Plesk updates.

Resolution

The error occurs when Plesk Migrator attempts to fix connection strings and obsolete paths in *.config files. As a workaround:

• Connect to the source server via RDP and shorten the path, or
• After migration, connect to the target server via RDP and fix any connection strings/obsolete paths in the .config files if necessary.