diff --git a/doc/bugs/git-annex-migrate_fails.mdwn b/doc/bugs/git-annex-migrate_fails.mdwn
new file mode 100644
index 0000000000..fd2e86d3e8
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+++ b/doc/bugs/git-annex-migrate_fails.mdwn
@@ -0,0 +1,26 @@
+Migrating from a URL key to an MD5E key (after addurl --fast using an external special remote) fails:
+
+    (master_env_py27_v28) [03:15 PM /data/ilya-work]$ git annex --verbose --debug migrate A4.taxfilt.bam
+    [2018-10-29 15:15:55.197015] read: git ["--git-dir=.git","--work-tree=.","--literal-pathspecs","ls-files","--cached","-z","--","A4.taxfilt.bam"]
+    [2018-10-29 15:15:55.232756] chat: git ["--git-dir=.git","--work-tree=.","--literal-pathspecs","check-attr","-z","--stdin","annex.backend","annex.numcopies","annex.largefiles","--"]
+    [2018-10-29 15:15:55.232934] read: git ["--version"]
+    [2018-10-29 15:15:55.233841] process done ExitSuccess
+    migrate A4.taxfilt.bam failed
+    [2018-10-29 15:15:55.263931] process done ExitSuccess
+    git-annex: migrate: 1 failed
+    (master_env_py27_v28) [03:15 PM /data/ilya-work]$ git annex info A4.taxfilt.bam
+    file: A4.taxfilt.bam
+    size: 12.75 megabytes
+    key: URL-s12750247--dx://file-FJZjKx800YQPJ5j589Q2Kfzv/A4.taxfilt.bam
+    present: true
+    (master_env_py27_v28) [03:16 PM /data/ilya-work]$ git annex whereis A4.taxfilt.bam
+    whereis A4.taxfilt.bam (2 copies)
+            0928dfcc-4dbe-4c24-a5a0-ac05c4a2c829 -- ilyas_main_repo [here]
+            6803648c-87e6-41ef-9570-48adb13ff59a -- [mydx]
+    
+      mydx: dx://file-FJZjKx800YQPJ5j589Q2Kfzv/A4.taxfilt.bam
+    ok
+    (master_env_py27_v28) [03:16 PM /data/ilya-work]$ git annex --verbose --debug migrate A4.taxfilt.bam --backend MD5E
+    [2018-10-29 15:17:15.621264] read: git ["--git-dir=.git","--work-tree=.","--literal-pathspecs","ls-files","--cached","-z","--","A4.taxfilt.bam"]
+    migrate A4.taxfilt.bam failed
+    git-annex: migrate: 1 failed