原因：安装过chrome，firefox或其它第三方浏览器导致outlook无法打开链接。
如果你尝试过
重设IE；
设置默认程序；
WORD Internet链接设置；
均无效。或者，
轻信了那些
“你的系统中毒了”
“重装系统吧”
之类的“后现代脑残型答案”后，还没有解决问题的话，往下看。
运行-》regedit-》
找到 HKEY_CURRENT_USER/Software/Classes/.html
右边默认值更改为：htmlfile
依次类推 .htm .shtml .xhtm .xhtml
打开outlook，点击email里的链接，IE窗口跳出来。
搞定。
如果帮到你，请回复。
1. Click Start, click Run, type Regedit in the Open box, and then click OK.
2. Locate the following subkey:
HKEY_CURRENT_USER/Software/Classes/.html
3. On the File menu, click Export.
4. In the Export Registry File dialog box, enter HKCU_Classes_HTML_Backup.reg and click Save.
Note: This will create a backup of this registry key in the My Documents folder by default.
5. Right click the (Default) value for the .html key and select Modify...
6. Change the value from "ChromeHTML" to "htmlfile"
Repeat steps 1-6 for .htm .shtml .xhtm and .xhtml keys if they exist, remember to change the name of your backup file for each export.