Hi,
I've a Website that sometimes goes down (blank response page). PHP reports this error:

[02-Sep-2016 10:02:32 Europe/Rome] PHP Fatal error: Uncaught Error: Class 'ComposerAutoloaderInit5a38a45c843f47dca48367ef93997d72' not found in D:\Websites\.........\concrete\vendor\autoload.php:7
Stack trace:
#0 D:\Websites\........\application\bootstrap\autoload.php(8): include()
#1 D:\Websites\........\concrete\bootstrap\autoload.php(8): include('D:\\Websites\\...')
#2 D:\Websites\........\concrete\dispatcher.php(27): require('D:\\Websites\\...')
#3 D:\Websites\........\index.php(2): require('D:\\Websites\\...')
#4 {main}
thrown in D:\Websites\........\concrete\vendor\autoload.php on line 7

I need to recycle the Website, then it restarts and works well.
Any idea?

Thanks

# concrete5 Version
Core Version - 5.7.5.8
Version Installed - 5.7.5.8
Database Version - 20160412000000

# concrete5 Packages
None

# concrete5 Cache Settings
Block Cache - On
Overrides Cache - On
Full Page Caching - Off
Full Page Cache Lifetime - Every 6 hours (default setting).

# Server Software
Microsoft-IIS/8.0

# Server API
cgi-fcgi

# PHP Version
7.0.9

# PHP Extensions
bcmath, calendar, cgi-fcgi, Core, ctype, curl, date, dom, exif, filter, gd, gettext, hash, iconv, imap, json, libxml, mbstring, mcrypt, mysqli, mysqlnd, openssl, pcre, PDO, pdo_mysql, pdo_sqlite, Phar, Reflection, session, SimpleXML, soap, SPL, standard, tidy, tokenizer, wddx, wincache, xml, xmlreader, xmlrpc, xmlwriter, zip, zlib.

# PHP Settings
max_execution_time - 300
log_errors_max_len - 1024
max_file_uploads - 20
max_input_nesting_level - 64
max_input_time - 60
max_input_vars - 1000
memory_limit - 128M
post_max_size - 20M
sql.safe_mode - Off
upload_max_filesize - 30M
mysqli.max_links - Unlimited
mysqli.max_persistent - Unlimited
pcre.backtrack_limit - 1000000
pcre.recursion_limit - 100000
session.cache_limiter - <i>no value</i>
session.gc_maxlifetime - 7200
soap.wsdl_cache_limit - 5
wincache.maxfilesize - 256
wincache.ttlmax - 1200