This operation has been canceled due to restrictions in effect on this computer. Please contact your system administrator.

Do you have this error?
I've seen it before, and recently saw it again.  But I noticed I didn't have it on my internet cache of things I do all the time, so I'm adding it here.
First,
Close Outlook
Then reset IE to factory defaults
(Tools, Internet Options, Advanced Tab, Reset, click the checkbox for personal settings also.)
Let it do its thing, close IE and open it back up
Selected the option to set IE as the default browser and try Outlook links again.

Still not working?
Time for some regediting
go to the registry editor (run 'regedit') and find this path:
HKEY_CURRENT_USER\Software\Classes\
we are going to change .html extensions from either ChromeHTML or FireFoxHTML to HTMLfile.
I also go through and change .htm, .xhtml, etc. to HTMLfile.  Whatever was pointing to Chrome of Firefox, change to HTMLfile.
Try Outlook again and you'll notice the 'restrictions' message doesn't come up, rather the linked webpage did.
If it didn't, make sure you followed the directions here, if it still doesn't work let me know if you find some other solution!

Excel: the file is corrupt and cannot be opened

I take 0 credit in this post, it is complete and utter rip from here:
http://www.ablebits.com/office-addins-blog/2011/11/30/excel-open-corrupt-files/
If you get this error:

1. Open the application.
2. Click on File -> Options.
3. Select Trust Center and press the Trust center settings button.
   
4. Pick Protected view.
   
5. Uncheck all the options under Protected View and confirm by pressing OK.
6. Restart Excel and try to open the broken Excel documents.

Back to my words.
This worked for me recently when a user couldn't open a document that everyone else could.  I tried opening and resaving the document, tried opening from different locations.  Different users saved it for her and sent it, nothing worked.  I found this gem at http://www.ablebits.com/office-addins-blog/2011/11/30/excel-open-corrupt-files/ and was able to resolve the issue.

Thanks again Ablebits!

Before deleting E-Mail account containing your personal mail, contacts and calender data, you must create a new location for your data

Have you ever had the error:

"Before deleting E-Mail account containing your personal mail, contacts and calender data, you must create a new location for your data. To create a new data location, open the Account Settings dialog box, click the Data Files tab, and then click Add."

when trying to remove an exchange email account from Email Account?

Well I have.

Usually when I'm running my general outlook fix because there are random issues with outlook.

Well I googled my way to another answer.

When you get the error:

"Before deleting E-Mail account containing your personal mail, contacts and calender data, you must create a new location for your data. To create a new data location, open the Account Settings dialog box, click the Data Files tab, and then click Add."

Simply remove the profile.

When you go to the Mail applet, select Show Profiles, and remove the profile that is there. 

Also, You will have to create a new profile before adding the email account.