{"id":9168,"date":"2009-09-16T17:48:30","date_gmt":"2009-09-16T16:48:30","guid":{"rendered":"http:\/\/onsoftware.en.softonic.com\/fix-for-nvdaopengl-channel-exception-imac-error\/"},"modified":"2025-07-02T02:20:20","modified_gmt":"2025-07-02T09:20:20","slug":"fix-for-nvdaopengl-channel-exception-imac-error","status":"publish","type":"post","link":"https:\/\/cms-articles.softonic.io\/en\/fix-for-nvdaopengl-channel-exception-imac-error\/","title":{"rendered":"Fix for NVDA(OpenGL): Channel exception! iMac error"},"content":{"rendered":"<p>\u00a0A few months back, I started having problems with my beloved iMac. Lines would appear on the screen, as well as patches of odd color. But worst of all was the series of system crashes I suddenly started suffering, often more than once a day. They&#8217;d happen while using Firefox, or opening a stack on the Dock, or just moving my mouse.<\/p>\n<p style=\"text-align: center\"><img decoding=\"async\" src=\"https:\/\/articles-images.sftcdn.net\/wp-content\/uploads\/sites\/3\/2009\/09\/imac-nvdaopengl-error-1.png\" alt=\"imac-nvdaopengl-error-1.png\" \/><\/p>\n<p>I tried disconnecting peripheral devices, used <a href=\"http:\/\/www.micromat.com\/index.php?Itemid=51&amp;id=37&amp;option=com_content&amp;task=view\"><strong>TechTool Deluxe<\/strong><\/a> to test the integrity of my hard disk and memory, but found no solution. Looking at <strong>Console <\/strong>for a clue (I probably should have done this first), I found lots of serious looking errors occurring just before my system crashes. They all took the form of:<\/p>\n<p><code>21.06.09 22:25:31 kernel NVDAOpenGL: Channel exception!  status  0xffff info32  0x3  Fifo: Unknown Method Error<br \/>\n<\/code><code>21.06.09 22:25:31<\/code><code> kernel 0000000b<\/code><\/p>\n<p>Now, I may not be a Mac expert per se, but my experiences working with OS X, Windows and Linux told me that &#8220;NVDA&#8221;, &#8220;OpenGL&#8221; and &#8220;Channel exception!&#8221; pointed to the fact that something was gravely wrong and that it had something to do with my Nvidia 7300 GT video card. Which begged the question: <strong>is this a hardware or a driver issue?<\/strong><\/p>\n<p>Reading <a href=\"http:\/\/discussions.apple.com\/thread.jspa?threadID=1916253\"><strong>this helpful thread<\/strong><\/a> on the Apple Support forums, I&#8217;ve found that plenty of other iMac owners are suffering with the same problem. Consensus there is that it&#8217;s related to a driver\/software fault&#8230; but this is confused by there being at least two problems which cause similar issues. User Asrenzo&#8217;s <a href=\"http:\/\/discussions.apple.com\/message.jspa?messageID=10214209#10214209\">comment<\/a> from yesterday helps to clarify the situation. After carrying out various tests, he feels certain that the software\/driver theory is right. It seems that OS X 10.5.7 introduced a new, faulty driver for the Nvidia graphics card which simply stopped it from working properly.<\/p>\n<p>&#8220;<strong>But what about the fix?<\/strong>&#8220;, you may be wondering. Well, the solution I&#8217;ve found is simple: <strong>install Snow Leopard<\/strong>. In my case, I backed up my entire home disk with Time Machine, erased and did a <strong>clean install<\/strong>, and then imported my apps, files and accounts from Time Machine. I&#8217;m not sure that the Time Machine bit is essential but I can say that not only does my 3 year-old iMac run like new now, I&#8217;ve also yet to see any Channel exception! or NVDA(OpenGL) errors.<\/p>\n<p>If you&#8217;re suffering with frequent crashes and are at your wit&#8217;s end (and your Mac&#8217;s <a href=\"http:\/\/www.apple.com\/macosx\/specs.html\">compatible<\/a>, of course), try doing a clean install of Snow Leopard. It certainly seems to have worked for me.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u00a0A few months back, I started having problems with my beloved iMac. Lines would appear on the screen, as well as patches of odd color. But worst of all was the series of system crashes I suddenly started suffering, often more than once a day. They&#8217;d happen while using Firefox, or opening a stack on &hellip; <a href=\"https:\/\/cms-articles.softonic.io\/en\/fix-for-nvdaopengl-channel-exception-imac-error\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Fix for NVDA(OpenGL): Channel exception! iMac error&#8221;<\/span><\/a><\/p>\n","protected":false},"author":2002,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","wpcf-pageviews":0},"categories":[2441],"tags":[],"usertag":[],"vertical":[],"content-category":[],"class_list":["post-9168","post","type-post","status-publish","format-standard","hentry","category-how-to"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/posts\/9168","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/users\/2002"}],"replies":[{"embeddable":true,"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/comments?post=9168"}],"version-history":[{"count":1,"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/posts\/9168\/revisions"}],"predecessor-version":[{"id":335374,"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/posts\/9168\/revisions\/335374"}],"wp:attachment":[{"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/media?parent=9168"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/categories?post=9168"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/tags?post=9168"},{"taxonomy":"usertag","embeddable":true,"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/usertag?post=9168"},{"taxonomy":"vertical","embeddable":true,"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/vertical?post=9168"},{"taxonomy":"content-category","embeddable":true,"href":"https:\/\/cms-articles.softonic.io\/en\/wp-json\/wp\/v2\/content-category?post=9168"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}