Generally you should know that TYPO3 generates temporary “cached” scripts in typo3conf/. Those would look like these:
-rw-r--r-- 1 httpd httpd 27501 Jan 29 18:35 temp_CACHED_ps2d95_ext_localconf.php
-rw-r--r-- 1 httpd httpd 83513 Jan 29 18:35 temp_CACHED_ps2d95_ext_tables.php
You can experience more than these files. In that case it will be because of multiple paths, symlinks or just old files.
You can at any time remove these files and on the next hit to the system they will be re-written. These files simply contains all ext_tables.php and ext_localconf.php files from the installed extensions concatenated in the order they are loaded. Therefore including one of these files would be the same as including potentially hundred PHP-files and that saves some milliseconds for the system.
But it also means that a) you can never make any local changes to these files since they can at anytime be removed and recreated from the “originals” and b) if you make changes to the original “ext_tables.php”/”ext_localconf.php” files you will have to clear these files away!
if you change the path of the TYPO3 installation you might see something like this:
Warning: Unable to access /www/htdocs/typo3/32/testsite-3.6.0/typo3conf//www/htdocs/typo3/32/testsite-3.6.0/admindir/sysext/cms/tbl_cms.php in /www/htdocs/typo3/32/typo3_src-3.6.0RC1/t3lib/class.t3lib_div.php on line 2745Warning: Unable to access /www/htdocs/typo3/32/testsite-3.6.0/typo3conf//www/htdocs/typo3/32/testsite-3.6.0/admindir/sysext/cms/tbl_cms.php in /www/htdocs/typo3/32/typo3_src-3.6.0RC1/t3lib/class.t3lib_div.php on line 2745Warning: Failed opening '/www/htdocs/typo3/32/testsite-3.6.0/typo3conf//www/htdocs/typo3/32/testsite-3.6.0/admindir/sysext/cms/tbl_cms.php' for inclusion (include_path='.:/usr/local/lib/php') in /www/htdocs/typo3/32/typo3_src-3.6.0RC1/t3lib/class.t3lib_div.php on line 2745....
That will go on for pages. The problem is that absolute file paths are hard coded inside the files.
Fix: Manually remove the temp_CACHED_*.php files manually via FTP or the file system. Then hit the page again.
There are some situations known which can cause what looks like totally illogical problems after an upgrade:
If extensions override classes where functions have changed. Solution; try to disable extensions and enable them one by one again till it fails.
If a PHP-cache somehow fails to re-cache scripts, in particular if a change happened to a parent class overridden by a child class which was not updated. Solution; remove ALL cached PHP files (for PHP-Accelerator, remove "/tmp/phpa_*") and restart Apache.
