{"id":52603,"date":"2026-06-17T21:35:01","date_gmt":"2026-06-17T21:35:01","guid":{"rendered":"https:\/\/www.oracletutoring.ca\/blog\/?p=52603"},"modified":"2026-06-17T21:35:03","modified_gmt":"2026-06-17T21:35:03","slug":"computer-systems-virus-scans-and-date-modified","status":"publish","type":"post","link":"https:\/\/www.oracletutoring.ca\/blog\/computer-systems-virus-scans-and-date-modified\/","title":{"rendered":"Computer systems: virus scans and date modified"},"content":{"rendered":"\n<h2>Self-tutoring about computer systems: the tutor mentions an interesting discovery about virus scanners.<\/h2>\n<p>\nThe following is according to my understanding.<\/p>\n<p>\nI was researching why sometimes a file&#8217;s &#8220;last modified&#8221; date might be more recent than expected. What I found is surprising, but makes sense at the same time.\n<\/p>\n<p>\nApparently, some virus scanners can alter a file&#8217;s &#8220;last modified&#8221; date. The reason is that a given virus scanner may mark a file somehow in order to indicate it&#8217;s been scanned. Yet, that same marking, to the operating system, may mean the file has been modified.<\/p>\n<p>\nTo me, this makes sense, for this reason: when I haven&#8217;t run a full scan on a system for a few months, it takes noticeably longer than if one just did a full scan last week. Therefore, one might imagine the scanner marks the files as they are scanned. Then, next scan, the virus scanner may look at the file&#8217;s last modified date. If that was the result of a scan, it knows it needn&#8217;t scan that file again.<\/p>\n<p>Source:<\/p>\n<p><a href=\"https:\/\/learn.microsoft.com\/en-us\/answers\/questions\/2592910\/what-are-the-possible-causes-of-a-date-modified-ti\">learn.microsoft.com<\/a><\/p>\n<p>\n<a href=\"https:\/\/community.f-secure.com\/en\/discussion\/31311\/2nd-full-scan-is-not-faster\">community.f-secure.com<\/a><\/p>\nJack of <a href=\"https:\/\/www.oracletutoring.ca\">Oracle Tutoring by Jack and Diane,<\/a> Campbell River, BC.\n","protected":false},"excerpt":{"rendered":"<p>Self-tutoring about computer systems: the tutor mentions an interesting discovery about virus scanners. The following is according to my understanding. I was researching why sometimes a file&#8217;s &#8220;last modified&#8221; date might be more recent than expected. What I found is &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"more-link\" href=\"https:\/\/www.oracletutoring.ca\/blog\/computer-systems-virus-scans-and-date-modified\/\"> <span class=\"screen-reader-text\">Computer systems: virus scans and date modified<\/span> Read More &raquo;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2142],"tags":[4299,4300,3766],"class_list":["post-52603","post","type-post","status-publish","format-standard","hentry","category-computer-systems","tag-anti-virus","tag-date-modified","tag-files"],"_links":{"self":[{"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/posts\/52603","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/comments?post=52603"}],"version-history":[{"count":5,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/posts\/52603\/revisions"}],"predecessor-version":[{"id":52608,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/posts\/52603\/revisions\/52608"}],"wp:attachment":[{"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/media?parent=52603"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/categories?post=52603"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/tags?post=52603"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}