I'm fairly new to PHP programming, so I'm just tossing this out there to see what the more exprerienced folks think: During a restore of a sizable course backup file, the process kept failing due to a memory limit error. I adjusted the memory limit in php.ini to 256M (which I think is a bit much), and it still pukes. Looking at the code, I notice the use of gzinflate (Zlib) in the pclzip.lib.php. Is that the best library to use? It seems the gz* functions are oriented towards compression/decompression of content sent to and from the user-agent, and not so much for files. The line (3806) where the memory limit error occurs look like: $v_file_content = @gzinflate($v_buffer); It happens that the file content being inflated (moodle.xml) is 198MB. I was thinking the regular Zip libraries might work a little better. So in moodlelib.php, unzip_file function, at about line 7343, I made this change: /* include_once("$CFG->libdir/pclzip/pclzip.lib.php"); $archive = new PclZip(cleardoubleslashes("$zippath/$zipfilename")); if (!$list = $archive->extract(PCLZIP_OPT_PATH, $destpath, PCLZIP_CB_PRE_EXTRACT, 'unzip_cleanfilename', PCLZIP_OPT_EXTRACT_DIR_RESTRICTION, $destpath)) { if (!empty($showstatus)) { notice($archive->errorInfo(true)); } return false; } */ $archive = new ZipArchive(); if (true === ($res = $archive->open(cleardoubleslashes("$zippath/$zipfilename")))) { $archive->extractTo($destpath); $archive->close(); } elseif (!empty($showstatus)) { notice('Unzip of file failed, code:' . $res); } No more memory limit error. I've even lowered the memory_limit setting in php.ini to 64M. Regards.