PST and OST are Outlook file formats. PST is the format used by Outlook for backups (mailbox data that is exported<\/a> and then imported<\/a>). OST is the format used by Outlook to keep a local cached<\/a> copy of the mailbox data. By default, starting from the Outlook 2010 version desktop application is able to open .pst files and create .ost which size is not more than 50 GB. If you try to open the .pst file of more than 50 GB, you will receive the following error:<\/p>\n\n\n\n Important: <\/strong>It is not recommended to have an .ost file of more than 50GB or open a .pst file larger than 50 GB as it might cause an Outlook profile corruption<\/a>. If your .ost file has reached the limit, it is recommended to decrease the size of the .ost file<\/a> instead of increasing the file limits. However, you might need to do this temporarily to upload the data from the .pst file to the server and you will find instructions for this below.<\/p>\n\n\n\n In order to increase the maximum size of the .pst and .ost files that your Outlook can open or create you will need to add or modify the following Windows registry entries:<\/p>\n\n\n\n These settings apply to both .ost and .pst files.<\/p>\n\n\n\n Important:<\/strong> it is recommended that the values between the MaxLargeFileSize registry entry and the WarnLargeFileSize registry entry differ by at least 5 percent (%) so that internal processes are not hindered from continuing.<\/p>\n\n\n\n In order to modify the Windows registry entries, follow these steps:<\/p>\n\n\n\n Despite the fact that you will be able to open .pst files that are larger than 50GB after making the described above registry changes, it can significantly decrease the performance of your Outlook application. <\/p>\n","protected":false},"excerpt":{"rendered":" Important: This article only applies to Outlook for Windows. PST and OST are Outlook file formats. PST is the format used by Outlook for backups (mailbox data that is exported and then imported). OST is the format used by Outlook to keep a local cached copy of the mailbox data. By default, starting from the Outlook 2010 version desktop application is […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[4,5],"tags":[],"class_list":["post-117","post","type-post","status-publish","format-standard","category-knowledge-base","category-microsoft","entry"],"_links":{"self":[{"href":"https:\/\/remoteapple.com\/index.php?rest_route=\/wp\/v2\/posts\/117","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/remoteapple.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/remoteapple.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/remoteapple.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/remoteapple.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=117"}],"version-history":[{"count":0,"href":"https:\/\/remoteapple.com\/index.php?rest_route=\/wp\/v2\/posts\/117\/revisions"}],"wp:attachment":[{"href":"https:\/\/remoteapple.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=117"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/remoteapple.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=117"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/remoteapple.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=117"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"\/](\"https:\/\/support.intermedia.com\/euf\/assets\/images\/answers\/osvc\/17301\/17301_1.png\")
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Note:<\/strong> if the PST key of the path above doesn’t exist, create it by right-clicking on the previous key in the registry (Outlook) > New > Key > enter the name PST <\/strong>> press Enter<\/strong>.<\/em>![\"\"](\"https:\/\/support.intermedia.com\/euf\/assets\/images\/answers\/osvc\/17301\/17301_4.png\")
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Note:<\/strong> if the entry doesn’t exist, create it by right-clicking on the empty space in the right pane > New > DWORD (32-bit) Value > type in MaxLargeFileSize<\/strong> > press Enter<\/strong>.<\/em>![\"\"](\"https:\/\/support.intermedia.com\/euf\/assets\/images\/answers\/osvc\/17301\/17301_6.png\")
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