• Plesk Uservoice will be deprecated by October. Moving forward, all product feature requests and improvement suggestions will be managed through our new platform Plesk Productboard.
    To continue sharing your ideas and feedback, please visit features.plesk.com

Issue Migration Failure: Classic to Integrated Mode Conversion Fails Due to UTF-8 Decode Error

Rabah

New Pleskian
Server operating system version
Windows Server 2022
Plesk version and microupdate number
Plesk Obsidian 18.0.70 Update #3 Web Host Edition
Hi,

We’re facing a migration failure during conversion of Classic app pools to Integrated mode, matching the issue described here: Failed to allow applications in Classic to work in Integrated mode after migration in web.config files

Migration Scenario:

I'm running a migration using Plesk Migrator:
  • Source Server: Windows Server 2012
  • Target Server: Windows Server 2022
Observed Error Logs (from Plesk Migrator):

Failed to allow applications in Classic to work in Integrated mode after migration in web.config files
Migration tools tried to perform operation in 3 attempts: 'utf-8' codec can't decode byte 0xff in position 57: invalid start byte

Debug Messages:


2025-08-05 15:17:43 Exception
Exception:
Traceback (most recent call last):
File "C:\Program Files (x86)\Plesk\admin\plib\modules\panel-migrator\backend\lib\python\parallels\core\safe.py", line 191, in try_subscription_with_rerun
func()
File "C:\Program Files (x86)\Plesk\admin\plib\modules\panel-migrator\backend\lib\python\parallels\core\workflow\runner\by_subscription.py", line 526, in <lambda>
lambda: action.run(self._context, subscription),
File "C:\Program Files (x86)\Plesk\admin\plib\modules\panel-migrator\backend\lib\python\parallels\core\actions\fix_web_config_integrated_mode.py", line 134, in run
runner.execute_command(
File "C:\Program Files (x86)\Plesk\admin\plib\modules\panel-migrator\backend\lib\python\parallels\core\runners\base.py", line 131, in execute_command
str_decode(execution_results.stdout, output_encoding),
File "C:\Program Files (x86)\Plesk\admin\plib\modules\panel-migrator\backend\lib\python\parallels\core\utils\common\string_utils.py", line 119, in str_decode
return s.decode(encoding)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xa0 in position 57: invalid start byte

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "C:\Program Files (x86)\Plesk\admin\plib\modules\panel-migrator\backend\lib\python\parallels\core\safe.py", line 164, in try_subscription
yield
File "C:\Program Files (x86)\Plesk\admin\plib\modules\panel-migrator\backend\lib\python\parallels\core\safe.py", line 197, in try_subscription_with_rerun
raise MultipleAttemptsMigrationError(exceptions)
parallels.core.safe.MultipleAttemptsMigrationError: Migration tools tried to perform operation in 3 attempts: 'utf-8' codec can't decode byte 0xa0 in position 57: invalid start byte
2025-08-05 15:17:43 Error
Failed to perform an action on subscription 'example.com': Failed to allow applications in Classic to work in Integrated mode after migration in web.config files Exception message: Migration tools tried to perform operation in 3 attempts: 'utf-8' codec can't decode byte 0xa0 in position 57: invalid start byte

Diagnostics:
  • Verified web.config file is UTF-8 encoded (no BOM).
  • Inspected the flagged line, no unusual characters found.
  • Hex-level analysis confirmed no invalid bytes at the reported offset.
Request:

Is there an updated patch or fix for this migrator issue (potential regression PMT‑5599)?

Thanks,
 
Back
Top