From bddf4079fd07762e3588c6c5928648c1d6c422f5 Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@z.cash>
Date: Wed, 4 Jan 2017 17:58:07 +0100
Subject: [PATCH 1/2] Instruct users to run zcash-fetch-params if network
 params aren't available

Closes #1786.
---
 src/init.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/init.cpp b/src/init.cpp
index 53f6fb832..6b87a5870 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -621,6 +621,17 @@ static void ZC_LoadParams()
     boost::filesystem::path pk_path = ZC_GetParamsDir() / "sprout-proving.key";
     boost::filesystem::path vk_path = ZC_GetParamsDir() / "sprout-verifying.key";
 
+    if (!(boost::filesystem::exists(pk_path) && boost::filesystem::exists(vk_path))) {
+        uiInterface.ThreadSafeMessageBox(strprintf(
+            _("Cannot find the Zcash network parameters in the following directory:\n"
+              "%s\n"
+              "Please run 'zcash-fetch-params' and then restart."),
+                ZC_GetParamsDir()),
+            "", CClientUIInterface::MSG_ERROR);
+        StartShutdown();
+        return;
+    }
+
     pzcashParams = ZCJoinSplit::Unopened();
 
     LogPrintf("Loading verifying key from %s\n", vk_path.string().c_str());

From 0b0a48c88149180f93c2f869f684ae1feffde73c Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@z.cash>
Date: Thu, 5 Jan 2017 11:38:38 +0100
Subject: [PATCH 2/2] Suggest ./zcutil/fetch-params.sh as well

Once we improve the from-source installation docs to use 'make install', we can
revert this commit.
---
 src/init.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/init.cpp b/src/init.cpp
index 6b87a5870..f85899667 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -625,7 +625,7 @@ static void ZC_LoadParams()
         uiInterface.ThreadSafeMessageBox(strprintf(
             _("Cannot find the Zcash network parameters in the following directory:\n"
               "%s\n"
-              "Please run 'zcash-fetch-params' and then restart."),
+              "Please run 'zcash-fetch-params' or './zcutil/fetch-params.sh' and then restart."),
                 ZC_GetParamsDir()),
             "", CClientUIInterface::MSG_ERROR);
         StartShutdown();