diff --git a/pageant.c b/pageant.c
index 0ca6b950..4d69cb5e 100644
--- a/pageant.c
+++ b/pageant.c
@@ -416,7 +416,7 @@ static void add_keyfile(Filename filename)
 	int i, nkeys, bloblen;
 
 	if (type == SSH_KEYTYPE_SSH1) {
-	    if (!rsakey_pubblob(&filename, &blob, &bloblen)) {
+	    if (!rsakey_pubblob(&filename, &blob, &bloblen, NULL)) {
 		MessageBox(NULL, "Couldn't load private key.", APPNAME,
 			   MB_OK | MB_ICONERROR);
 		return;
@@ -424,7 +424,7 @@ static void add_keyfile(Filename filename)
 	    keylist = get_keylist1();
 	} else {
 	    unsigned char *blob2;
-	    blob = ssh2_userkey_loadpub(&filename, NULL, &bloblen);
+	    blob = ssh2_userkey_loadpub(&filename, NULL, &bloblen, NULL);
 	    if (!blob) {
 		MessageBox(NULL, "Couldn't load private key.", APPNAME,
 			   MB_OK | MB_ICONERROR);
@@ -498,9 +498,9 @@ static void add_keyfile(Filename filename)
 	} else
 	    *passphrase = '\0';
 	if (type == SSH_KEYTYPE_SSH1)
-	    ret = loadrsakey(&filename, rkey, passphrase);
+	    ret = loadrsakey(&filename, rkey, passphrase, NULL);
 	else {
-	    skey = ssh2_load_userkey(&filename, passphrase);
+	    skey = ssh2_load_userkey(&filename, passphrase, NULL);
 	    if (skey == SSH2_WRONG_PASSPHRASE)
 		ret = -1;
 	    else if (!skey)
diff --git a/puttygen.c b/puttygen.c
index fce91cf5..3e43b052 100644
--- a/puttygen.c
+++ b/puttygen.c
@@ -681,14 +681,14 @@ void load_key_file(HWND hwnd, struct MainDlgState *state,
 	if (type == SSH_KEYTYPE_SSH1) {
 	    if (realtype == type)
 		ret = loadrsakey(&filename, &newkey1,
-				 passphrase);
+				 passphrase, NULL);
 	    else
 		ret = import_ssh1(&filename, realtype,
 				  &newkey1, passphrase);
 	} else {
 	    if (realtype == type)
 		newkey2 = ssh2_load_userkey(&filename,
-					    passphrase);
+					    passphrase, NULL);
 	    else
 		newkey2 = import_ssh2(&filename, realtype,
 				      passphrase);
diff --git a/ssh.c b/ssh.c
index 23602f6d..33da9930 100644
--- a/ssh.c
+++ b/ssh.c
@@ -2602,7 +2602,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
     if (!filename_is_null(ssh->cfg.keyfile)) {
 	if (!rsakey_pubblob(&ssh->cfg.keyfile,
-			    &s->publickey_blob, &s->publickey_bloblen))
+			    &s->publickey_blob, &s->publickey_bloblen, NULL))
 	    s->publickey_blob = NULL;
     } else
 	s->publickey_blob = NULL;
@@ -2888,11 +2888,15 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 	    s->tried_publickey = 1;
 	    
 	    {
-		int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password);
+		const char *error = NULL;
+		int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password,
+				     &error);
 		if (ret == 0) {
 		    c_write_str(ssh, "Couldn't load private key from ");
 		    c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
-		    c_write_str(ssh, ".\r\n");
+		    c_write_str(ssh, " (");
+		    c_write_str(ssh, error);
+		    c_write_str(ssh, ").\r\n");
 		    continue;	       /* go and try password */
 		}
 		if (ret == -1) {
@@ -4586,7 +4590,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 	    if (keytype == SSH_KEYTYPE_SSH2) {
 		s->publickey_blob =
 		    ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
-					 &s->publickey_bloblen);
+					 &s->publickey_bloblen, NULL);
 	    } else {
 		char *msgbuf;
 		logeventf(ssh, "Unable to use this key file (%s)",
@@ -4916,7 +4920,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 		pub_blob =
 		    (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
 							  &algorithm,
-							  &pub_blob_len);
+							  &pub_blob_len,
+							  NULL);
 		if (pub_blob) {
 		    ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
 		    ssh2_pkt_addstring(ssh, s->username);
@@ -5093,14 +5098,18 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 		 * We have our passphrase. Now try the actual authentication.
 		 */
 		struct ssh2_userkey *key;
+		const char *error = NULL;
 
-		key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password);
+		key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password,
+					&error);
 		if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
 		    if (key == SSH2_WRONG_PASSPHRASE) {
 			c_write_str(ssh, "Wrong passphrase\r\n");
 			s->tried_pubkey_config = FALSE;
 		    } else {
-			c_write_str(ssh, "Unable to load private key\r\n");
+			c_write_str(ssh, "Unable to load private key (");
+			c_write_str(ssh, error);
+			c_write_str(ssh, ")\r\n");
 			s->tried_pubkey_config = TRUE;
 		    }
 		    /* Send a spurious AUTH_NONE to return to the top. */
diff --git a/ssh.h b/ssh.h
index 11f2d19e..3320098b 100644
--- a/ssh.h
+++ b/ssh.h
@@ -327,9 +327,10 @@ Bignum dh_create_e(void *, int nbits);
 Bignum dh_find_K(void *, Bignum f);
 
 int loadrsakey(const Filename *filename, struct RSAKey *key,
-	       char *passphrase);
+	       char *passphrase, const char **errorstr);
 int rsakey_encrypted(const Filename *filename, char **comment);
-int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen);
+int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen,
+		   const char **errorstr);
 
 int saversakey(const Filename *filename, struct RSAKey *key, char *passphrase);
 
@@ -344,9 +345,9 @@ extern struct ssh2_userkey ssh2_wrong_passphrase;
 
 int ssh2_userkey_encrypted(const Filename *filename, char **comment);
 struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
-				       char *passphrase);
+				       char *passphrase, const char **errorstr);
 char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,
-			   int *pub_blob_len);
+			   int *pub_blob_len, const char **errorstr);
 int ssh2_save_userkey(const Filename *filename, struct ssh2_userkey *key,
 		      char *passphrase);
 
diff --git a/sshpubk.c b/sshpubk.c
index d0594b77..1659acec 100644
--- a/sshpubk.c
+++ b/sshpubk.c
@@ -34,7 +34,8 @@
                           (x)=='/' ? 63 : 0 )
 
 static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only,
-			   char **commentptr, char *passphrase)
+			   char **commentptr, char *passphrase,
+			   const char **error)
 {
     unsigned char buf[16384];
     unsigned char keybuf[16];
@@ -44,13 +45,18 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only,
     struct MD5Context md5c;
     char *comment;
 
+    *error = NULL;
+
     /* Slurp the whole file (minus the header) into a buffer. */
     len = fread(buf, 1, sizeof(buf), fp);
     fclose(fp);
-    if (len < 0 || len == sizeof(buf))
+    if (len < 0 || len == sizeof(buf)) {
+	*error = "error reading file";
 	goto end;		       /* file too big or not read */
+    }
 
     i = 0;
+    *error = "file format error";
 
     /*
      * A zero byte. (The signature includes a terminating NUL.)
@@ -98,7 +104,9 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only,
     if (key)
 	key->comment = comment;
     if (!key) {
-	return ciphertype != 0;
+	ret = ciphertype != 0;
+	*error = NULL;
+	goto end;
     }
 
     /*
@@ -119,6 +127,7 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only,
     if (len - i < 4)
 	goto end;
     if (buf[i] != buf[i + 2] || buf[i + 1] != buf[i + 3]) {
+	*error = "wrong passphrase";
 	ret = -1;
 	goto end;
     }
@@ -143,6 +152,7 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only,
 	goto end;
 
     if (!rsa_verify(key)) {
+	*error = "rsa_verify failed";
 	freersakey(key);
 	ret = 0;
     } else
@@ -153,28 +163,39 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only,
     return ret;
 }
 
-int loadrsakey(const Filename *filename, struct RSAKey *key, char *passphrase)
+int loadrsakey(const Filename *filename, struct RSAKey *key, char *passphrase,
+	       const char **errorstr)
 {
     FILE *fp;
     char buf[64];
+    int ret = 0;
+    const char *error = NULL;
 
     fp = f_open(*filename, "rb");
-    if (!fp)
-	return 0;		       /* doesn't even exist */
+    if (!fp) {
+	error = "can't open file";
+	goto end;
+    }
 
     /*
      * Read the first line of the file and see if it's a v1 private
      * key file.
      */
     if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {
-	return loadrsakey_main(fp, key, FALSE, NULL, passphrase);
+	ret = loadrsakey_main(fp, key, FALSE, NULL, passphrase, &error);
+	goto end;
     }
 
     /*
      * Otherwise, we have nothing. Return empty-handed.
      */
     fclose(fp);
-    return 0;
+    error = "not an SSH-1 RSA file";
+
+  end:
+    if ((ret != 1) && errorstr)
+	*errorstr = error;
+    return ret;
 }
 
 /*
@@ -195,7 +216,8 @@ int rsakey_encrypted(const Filename *filename, char **comment)
      * key file.
      */
     if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {
-	return loadrsakey_main(fp, NULL, FALSE, comment, NULL);
+	const char *dummy;
+	return loadrsakey_main(fp, NULL, FALSE, comment, NULL, &dummy);
     }
     fclose(fp);
     return 0;			       /* wasn't the right kind of file */
@@ -206,12 +228,14 @@ int rsakey_encrypted(const Filename *filename, char **comment)
  * an RSA key, as given in the agent protocol (modulus bits,
  * exponent, modulus).
  */
-int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen)
+int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen,
+		   const char **errorstr)
 {
     FILE *fp;
     char buf[64];
     struct RSAKey key;
     int ret;
+    const char *error = NULL;
 
     /* Default return if we fail. */
     *blob = NULL;
@@ -219,8 +243,10 @@ int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen)
     ret = 0;
 
     fp = f_open(*filename, "rb");
-    if (!fp)
-	return 0;		       /* doesn't even exist */
+    if (!fp) {
+	error = "can't open file";
+	goto end;
+    }
 
     /*
      * Read the first line of the file and see if it's a v1 private
@@ -228,13 +254,19 @@ int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen)
      */
     if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {
 	memset(&key, 0, sizeof(key));
-	if (loadrsakey_main(fp, &key, TRUE, NULL, NULL)) {
+	if (loadrsakey_main(fp, &key, TRUE, NULL, NULL, &error)) {
 	    *blob = rsa_public_blob(&key, bloblen);
 	    freersakey(&key);
 	    ret = 1;
 	}
+    } else {
+	error = "not an SSH-1 RSA file";
+        fclose(fp);
     }
-    fclose(fp);
+
+  end:
+    if ((ret != 1) && errorstr)
+	*errorstr = error;
     return ret;
 }
 
@@ -575,7 +607,7 @@ struct ssh2_userkey ssh2_wrong_passphrase = {
 };
 
 struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
-				       char *passphrase)
+				       char *passphrase, const char **errorstr)
 {
     FILE *fp;
     char header[40], *b, *encryption, *comment, *mac;
@@ -586,14 +618,17 @@ struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
     int public_blob_len, private_blob_len;
     int i, is_mac, old_fmt;
     int passlen = passphrase ? strlen(passphrase) : 0;
+    const char *error = NULL;
 
     ret = NULL;			       /* return NULL for most errors */
     encryption = comment = mac = NULL;
     public_blob = private_blob = NULL;
 
     fp = f_open(*filename, "rb");
-    if (!fp)
+    if (!fp) {
+	error = "can't open file";
 	goto error;
+    }
 
     /* Read the first header line which contains the key type. */
     if (!read_header(fp, header))
@@ -604,8 +639,11 @@ struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
 	/* this is an old key file; warn and then continue */
 	old_keyfile_warning();
 	old_fmt = 1;
-    } else
+    } else {
+	error = "not a PuTTY SSH-2 private key";
 	goto error;
+    }
+    error = "file format error";
     if ((b = read_body(fp)) == NULL)
 	goto error;
     /* Select key algorithm structure. */
@@ -769,7 +807,12 @@ struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
 	if (strcmp(mac, realmac)) {
 	    /* An incorrect MAC is an unconditional Error if the key is
 	     * unencrypted. Otherwise, it means Wrong Passphrase. */
-	    ret = cipher ? SSH2_WRONG_PASSPHRASE : NULL;
+	    if (cipher) {
+		ret = SSH2_WRONG_PASSPHRASE;
+	    } else {
+		error = "MAC failed";
+		ret = NULL;
+	    }
 	    goto error;
 	}
     }
@@ -787,10 +830,13 @@ struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
 	sfree(ret->comment);
 	sfree(ret);
 	ret = NULL;
+	error = "createkey failed";
+	goto error;
     }
     sfree(public_blob);
     sfree(private_blob);
     sfree(encryption);
+    *errorstr = NULL;
     return ret;
 
     /*
@@ -809,11 +855,13 @@ struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
 	sfree(public_blob);
     if (private_blob)
 	sfree(private_blob);
+    if (errorstr)
+	*errorstr = error;
     return ret;
 }
 
 char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,
-			   int *pub_blob_len)
+			   int *pub_blob_len, const char **errorstr)
 {
     FILE *fp;
     char header[40], *b;
@@ -821,18 +869,24 @@ char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,
     unsigned char *public_blob;
     int public_blob_len;
     int i;
+    const char *error = NULL;
 
     public_blob = NULL;
 
     fp = f_open(*filename, "rb");
-    if (!fp)
+    if (!fp) {
+	error = "can't open file";
 	goto error;
+    }
 
     /* Read the first header line which contains the key type. */
     if (!read_header(fp, header)
 	|| (0 != strcmp(header, "PuTTY-User-Key-File-2") &&
-	    0 != strcmp(header, "PuTTY-User-Key-File-1")))
+	    0 != strcmp(header, "PuTTY-User-Key-File-1"))) {
+	error = "not a PuTTY SSH-2 private key";
 	goto error;
+    }
+    error = "file format error";
     if ((b = read_body(fp)) == NULL)
 	goto error;
     /* Select key algorithm structure. Currently only ssh-rsa. */
@@ -885,6 +939,8 @@ char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,
 	fclose(fp);
     if (public_blob)
 	sfree(public_blob);
+    if (errorstr)
+	*errorstr = error;
     return NULL;
 }