--- a/services/history-v1/api/controllers/project_import.js
+++ b/services/history-v1/api/controllers/project_import.js
@@ -35,6 +35,7 @@ async function importSnapshot(req, res) {
   try {
     snapshot = Snapshot.fromRaw(rawSnapshot)
   } catch (err) {
+    logger.warn({ err, projectId }, 'failed to import snapshot')
     return render.unprocessableEntity(res)
   }

@@ -43,6 +44,7 @@ async function importSnapshot(req, res) {
     historyId = await chunkStore.initializeProject(projectId, snapshot)
   } catch (err) {
     if (err instanceof chunkStore.AlreadyInitialized) {
+      logger.warn({ err, projectId }, 'already initialized')
       return render.conflict(res)
     } else {
       throw err
--- a/services/history-v1/api/controllers/projects.js
+++ b/services/history-v1/api/controllers/projects.js
@@ -34,6 +34,7 @@ async function initializeProject(req, res, next) {
     res.status(HTTPStatus.OK).json({ projectId })
   } catch (err) {
     if (err instanceof chunkStore.AlreadyInitialized) {
+      logger.warn({ err, projectId }, 'failed to initialize')
       render.conflict(res)
     } else {
       throw err
@@ -242,11 +243,15 @@ async function createProjectBlob(req, res, next) {
     const sizeLimit = new StreamSizeLimit(maxUploadSize)
     await pipeline(req, sizeLimit, fs.createWriteStream(tmpPath))
     if (sizeLimit.sizeLimitExceeded) {
+      logger.warn(
+        { projectId, expectedHash, maxUploadSize },
+        'blob exceeds size threshold'
+      )
       return render.requestEntityTooLarge(res)
     }
     const hash = await blobHash.fromFile(tmpPath)
     if (hash !== expectedHash) {
-      logger.debug({ hash, expectedHash }, 'Hash mismatch')
+      logger.warn({ projectId, hash, expectedHash }, 'Hash mismatch')
       return render.conflict(res, 'File hash mismatch')
     }

@@ -343,6 +348,10 @@ async function copyProjectBlob(req, res, next) {
     targetBlobStore.getBlob(blobHash),
   ])
   if (!sourceBlob) {
+    logger.warn(
+      { sourceProjectId, targetProjectId, blobHash },
+      'missing source blob when copying across projects'
+    )
     return render.notFound(res)
   }
   // Exit early if the blob exists in the target project.
--- a/services/history-v1/app.js
+++ b/services/history-v1/app.js
@@ -100,11 +100,13 @@ function setupErrorHandling() {
       })
     }
     if (err.code === 'ENUM_MISMATCH') {
+      logger.warn({ err, projectId }, err.message)
       return res.status(HTTPStatus.UNPROCESSABLE_ENTITY).json({
         message: 'invalid enum value: ' + err.paramName,
       })
     }
     if (err.code === 'REQUIRED') {
+      logger.warn({ err, projectId }, err.message)
       return res.status(HTTPStatus.UNPROCESSABLE_ENTITY).json({
         message: err.message,
       })
--- a/services/project-history/app/js/HistoryStoreManager.js
+++ b/services/project-history/app/js/HistoryStoreManager.js
@@ -35,7 +35,10 @@ class StringStream extends stream.Readable {
 _mocks.getMostRecentChunk = (projectId, historyId, callback) => {
   const path = `projects/${historyId}/latest/history`
   logger.debug({ projectId, historyId }, 'getting chunk from history service')
-  _requestChunk({ path, json: true }, callback)
+  _requestChunk({ path, json: true }, (err, chunk) => {
+    if (err) return callback(OError.tag(err))
+    callback(null, chunk)
+  })
 }

 /**
@@ -54,7 +57,10 @@ export function getChunkAtVersion(projectId, historyId, version, callback) {
     { projectId, historyId, version },
     'getting chunk from history service for version'
   )
-  _requestChunk({ path, json: true }, callback)
+  _requestChunk({ path, json: true }, (err, chunk) => {
+    if (err) return callback(OError.tag(err))
+    callback(null, chunk)
+  })
 }

 export function getMostRecentVersion(projectId, historyId, callback) {
@@ -68,8 +74,10 @@ export function getMostRecentVersion(projectId, historyId, callback) {
       _.sortBy(chunk.chunk.history.changes || [], x => x.timestamp)
     )
     // find the latest project and doc versions in the chunk
-    _getLatestProjectVersion(projectId, chunk, (err1, projectVersion) =>
+    _getLatestProjectVersion(projectId, chunk, (err1, projectVersion) => {
+      if (err1) err1 = OError.tag(err1)
       _getLatestV2DocVersions(projectId, chunk, (err2, v2DocVersions) => {
+        if (err2) err2 = OError.tag(err2)
         // return the project and doc versions
         const projectStructureAndDocVersions = {
           project: projectVersion,
@@ -83,7 +91,7 @@ export function getMostRecentVersion(projectId, historyId, callback) {
           chunk
         )
       })
-    )
+    })
   })
 }

@@ -211,7 +219,10 @@ export function getProjectBlob(historyId, blobHash, callback) {
   logger.debug({ historyId, blobHash }, 'getting blob from history service')
   _requestHistoryService(
     { path: `projects/${historyId}/blobs/${blobHash}` },
-    callback
+    (err, blob) => {
+      if (err) return callback(OError.tag(err))
+      callback(null, blob)
+    }
   )
 }

@@ -277,7 +288,10 @@ function createBlobFromString(historyId, data, fileId, callback) {
     (fsPath, cb) => {
       _createBlob(historyId, fsPath, cb)
     },
-    callback
+    (err, hash) => {
+      if (err) return callback(OError.tag(err))
+      callback(null, hash)
+    }
   )
 }

@@ -330,7 +344,7 @@ export function createBlobForUpdate(projectId, historyId, update, callback) {
     try {
       ranges = HistoryBlobTranslator.createRangeBlobDataFromUpdate(update)
     } catch (error) {
-      return callback(error)
+      return callback(OError.tag(error))
     }
     createBlobFromString(
       historyId,
@@ -338,7 +352,7 @@ export function createBlobForUpdate(projectId, historyId, update, callback) {
       `project-${projectId}-doc-${update.doc}`,
       (err, fileHash) => {
         if (err) {
-          return callback(err)
+          return callback(OError.tag(err))
         }
         if (ranges) {
           createBlobFromString(
@@ -347,7 +361,7 @@ export function createBlobForUpdate(projectId, historyId, update, callback) {
             `project-${projectId}-doc-${update.doc}-ranges`,
             (err, rangesHash) => {
               if (err) {
-                return callback(err)
+                return callback(OError.tag(err))
               }
               logger.debug(
                 { fileHash, rangesHash },
@@ -415,7 +429,7 @@ export function createBlobForUpdate(projectId, historyId, update, callback) {
             },
             (err, fileHash) => {
               if (err) {
-                return callback(err)
+                return callback(OError.tag(err))
               }
               if (update.hash && update.hash !== fileHash) {
                 logger.warn(
@@ -447,7 +461,7 @@ export function createBlobForUpdate(projectId, historyId, update, callback) {
               },
               (err, fileHash) => {
                 if (err) {
-                  return callback(err)
+                  return callback(OError.tag(err))
                 }
                 logger.debug({ fileHash }, 'created empty blob for file')
                 callback(null, { file: fileHash })
@@ -520,7 +534,10 @@ export function initializeProject(historyId, callback) {
 export function deleteProject(projectId, callback) {
   _requestHistoryService(
     { method: 'DELETE', path: `projects/${projectId}` },
-    callback
+    err => {
+      if (err) return callback(OError.tag(err))
+      callback(null)
+    }
   )
 }