Looks like the bots are dying during execution. https://chromium-swarm.appspot.com/task?id=41fcc7ab9c7e9610&refresh=10&show_raw=1&wide_logs=true is one of the swarming task page.


5792 2018-12-25 12:04:43.332 E: Error while removing named cache u'C:\\b\\swarming\\w\\ir\\cache\\vpython' at u'vpython'. The cache will be lost.
Traceback (most recent call last):
  File "C:\b\swarming\swarming_bot.1.zip\client\run_isolated.py", line 1376, in install_named_caches
    named_cache.uninstall(path, name)
  File "C:\b\swarming\swarming_bot.1.zip\client\local_caching.py", line 912, in uninstall
    name, path, ex))
NamedCacheError: cannot uninstall cache named u'vpython' at u'C:\\b\\swarming\\w\\ir\\cache\\vpython': [Error 5] Access is denied

is the error.

Marking as P3 since the bot recovered. Not sure if it's worth investigating anymore.

Thanks for reporting this Khushal. Since the bot recovered this was probably an infra change which was subsequently reverted. Let's close it.