title: VBA/Excel suddenly running slow with no code changes
body: <p>I came to work this morning and began work on the same file I left from yesterday.  Now Excel slows way down whenever a macro is assigning values to cells or clearing them.  It was lightning quick before I left yesterday, now it takes 2-3 seconds at a time to assign a value to a cell.</p>
  
  <p>Right now, other files with similar macros run fine.  This happened to another file a while back, so I reverted to a previous version of the file and it worked fine, while the slow file continued to work slow.  I guess I can do that now, but in this case that would take a whole lot of work to bring that file to where I have this version.  I was wondering if anyone knows what might be going on.  Is this one of the things Excel files just do from time to time (like a kind of file corruption), or is there a fix?</p>
  
  <p>I have provided the macro below, although it happens throughout the file whenever values are assigned to cells.  I've marked the trouble areas by denoting <code>&lt;---SLOW HERE</code>.</p>
  
  <p>I know this all sounds very vague, and I know I am giving very little to go on.  Perhaps insufficient info, but this is all I have.  There is no reason (that I can see) that this should be happening.  I've even restarted the computer...just in case the problem was external to Excel.  No change.</p>
  
  <p>If you need more info I will do my best to expound if I can.  Thanks for your help and understanding.</p>
  
  <p>Example Macro:</p>
  
  <pre><code>Sub DeleteButton1_Click()
     Call UnlockSettingsWorksheet
  
     Sheet24.Range("C18:E18").Value = ""  &lt;---SLOW HERE 
     Dim i As Long
     For i = 18 To 21
       Sheet24.Range("C" &amp; i &amp; ":E" &amp; i).Value = Sheet24.Range("C" &amp; i + 1 &amp; ":E" &amp; i + 1).Value  &lt;---SLOW HERE  
     Next
     Sheet24.Range("C22:E22").Value = ""  &lt;---SLOW HERE 
  
     Call LockSettingsWorksheet
  End Sub
  </code></pre>