TOC is not open in the .mxd.

[TraceyWiggins]

TOC is not open in an existing .mxd.  When user opens it via Windows>>Table of Contents it is maximized (full screen).  It cannot be resized, minimized, or pinned but can be closed.  Closed the existing .mxd.  Opened a blank ArcMap 10.3x .mxd and it is doing the same thing.  Suggestions?

[RobertScheitlin__GISP]

Tracey,

  First word of warning! What I am about to explain involves editing your windows registry and extreme Caution should be used.

Go to the start button in Windows and type "regedit" in the "Search programs and files" box and click enter.

Search for this key in the registry:

HKEY_CURRENT_USER\Software\ESRI\Desktop10.4\ArcMap\DockingPaneLayouts\panestate

Look through each of the pane-x listed there and find the one with a title of "Table Of Contents" (normally Pane-1) delete that key.

HKEY_CURRENT_USER\Software\ESRI\Desktop10.4\ArcMap\DockingPaneLayouts\panestate\Pane-1

restart ArcMap and the toc should be back in its normal spot.

[RebeccaStrauch__GISP]

Before going into the registry, you may want to try resetint your arcgis profile first

Resetting your ArcGIS application profile​

A little less drastic.  Also, if that doesn't work, you can also set up a new user, which creates a new windows profile, and see if it is an issue there.

Robert's suggestions will most likely work, but it will also require admin privileges (or should).  The first option above should not.