diff --git a/poky/meta/classes/sanity.bbclass b/poky/meta/classes/sanity.bbclass
index 894f0e3..e907a35 100644
--- a/poky/meta/classes/sanity.bbclass
+++ b/poky/meta/classes/sanity.bbclass
@@ -392,9 +392,12 @@
             msg = data.getVar('CONNECTIVITY_CHECK_MSG') or ""
             if len(msg) == 0:
                 msg = "%s.\n" % err
-                msg += "    Please ensure your host's network is configured correctly,\n"
-                msg += "    or set BB_NO_NETWORK = \"1\" to disable network access if\n"
-                msg += "    all required sources are on local disk.\n"
+                msg += "    Please ensure your host's network is configured correctly.\n"
+                msg += "    If your ISP or network is blocking the above URL,\n"
+                msg += "    try with another domain name, for example by setting:\n"
+                msg += "    CONNECTIVITY_CHECK_URIS = \"https://www.yoctoproject.org/\""
+                msg += "    You could also set BB_NO_NETWORK = \"1\" to disable network\n"
+                msg += "    access if all required sources are on local disk.\n"
             retval = msg
 
     return retval
@@ -882,13 +885,18 @@
         except:
             pass
 
-    oeroot = d.getVar('COREBASE')
-    if oeroot.find('+') != -1:
-        status.addresult("Error, you have an invalid character (+) in your COREBASE directory path. Please move the installation to a directory which doesn't include any + characters.")
-    if oeroot.find('@') != -1:
-        status.addresult("Error, you have an invalid character (@) in your COREBASE directory path. Please move the installation to a directory which doesn't include any @ characters.")
-    if oeroot.find(' ') != -1:
-        status.addresult("Error, you have a space in your COREBASE directory path. Please move the installation to a directory which doesn't include a space since autotools doesn't support this.")
+    for checkdir in ['COREBASE', 'TMPDIR']:
+        val = d.getVar(checkdir)
+        if val.find('..') != -1:
+            status.addresult("Error, you have '..' in your %s directory path. Please ensure the variable contains an absolute path as this can break some recipe builds in obtuse ways." % checkdir)
+        if val.find('+') != -1:
+            status.addresult("Error, you have an invalid character (+) in your %s directory path. Please move the installation to a directory which doesn't include any + characters." % checkdir)
+        if val.find('@') != -1:
+            status.addresult("Error, you have an invalid character (@) in your %s directory path. Please move the installation to a directory which doesn't include any @ characters." % checkdir)
+        if val.find(' ') != -1:
+            status.addresult("Error, you have a space in your %s directory path. Please move the installation to a directory which doesn't include a space since autotools doesn't support this." % checkdir)
+        if val.find('%') != -1:
+            status.addresult("Error, you have an invalid character (%) in your %s directory path which causes problems with python string formatting. Please move the installation to a directory which doesn't include any % characters." % checkdir)
 
     # Check the format of MIRRORS, PREMIRRORS and SSTATE_MIRRORS
     import re