diff --git a/protos/Backups.proto b/protos/Backups.proto
index 8cde79590..e93f29aea 100644
--- a/protos/Backups.proto
+++ b/protos/Backups.proto
@@ -31,6 +31,7 @@ message BackupInfo {
 // For example, Chats may all be together at the beginning,
 // or may each immediately precede its first ChatItem.
 message Frame {
+  // If unset, importers should skip this frame without throwing an error.
   oneof item {
     AccountData account = 1;
     Recipient recipient = 2;
@@ -45,13 +46,13 @@ message Frame {
 
 message AccountData {
   enum PhoneNumberSharingMode {
-    UNKNOWN = 0;
+    UNKNOWN = 0; // Interpret as "Nobody"
     EVERYBODY = 1;
     NOBODY = 2;
   }
   message UsernameLink {
     enum Color {
-      UNKNOWN = 0;
+      UNKNOWN = 0; // Interpret as "Blue"
       BLUE = 1;
       WHITE = 2;
       GREY = 3;
@@ -98,6 +99,7 @@ message AccountData {
   message IAPSubscriberData {
     bytes subscriberId = 1;
 
+    // If unset, importers should ignore the subscriber data without throwing an error.
     oneof iapSubscriptionId {
       // Identifies an Android Play Store IAP subscription.
       string purchaseToken = 2;
@@ -120,6 +122,7 @@ message AccountData {
 
 message Recipient {
   uint64 id = 1; // generated id for reference only within this file
+  // If unset, importers should skip this frame without throwing an error.
   oneof destination {
     Contact contact = 2;
     Group group = 3;
@@ -132,9 +135,9 @@ message Recipient {
 
 message Contact {
   enum IdentityState {
-    DEFAULT = 0;
+    DEFAULT = 0; // A valid value -- indicates unset by the user
     VERIFIED = 1;
-    UNVERIFIED = 2;
+    UNVERIFIED = 2; // Was once verified and is now unverified
   }
 
   message Registered {}
@@ -143,7 +146,7 @@ message Contact {
   }
 
   enum Visibility {
-    VISIBLE = 0;
+    VISIBLE = 0; // A valid value -- the contact is not hidden
     HIDDEN = 1;
     HIDDEN_MESSAGE_REQUEST = 2;
   }
@@ -160,6 +163,7 @@ message Contact {
   bool blocked = 5;
   Visibility visibility = 6;
 
+  // If unset, consider the user to be registered
   oneof registration {
     Registered registered = 7;
     NotRegistered notRegistered = 8;
@@ -178,7 +182,7 @@ message Contact {
 
 message Group {
   enum StorySendMode {
-    DEFAULT = 0;
+    DEFAULT = 0; // A valid value -- indicates unset by the user
     DISABLED = 1;
     ENABLED = 2;
   }
@@ -212,6 +216,7 @@ message Group {
   }
 
   message GroupAttributeBlob {
+    // If unset, consider the field it represents to not be present
     oneof content {
       string title = 1;
       bytes avatar = 2;
@@ -222,7 +227,7 @@ message Group {
 
   message Member {
     enum Role {
-      UNKNOWN = 0;
+      UNKNOWN = 0; // Intepret as "Default"
       DEFAULT = 1;
       ADMINISTRATOR = 2;
     }
@@ -254,7 +259,7 @@ message Group {
 
   message AccessControl {
     enum AccessRequired {
-      UNKNOWN = 0;
+      UNKNOWN = 0; // Intepret as "Unsatisfiable"
       ANY = 1;
       MEMBER = 2;
       ADMINISTRATOR = 3;
@@ -294,7 +299,7 @@ message Chat {
  */
 message CallLink {
   enum Restrictions {
-    UNKNOWN = 0;
+    UNKNOWN = 0; // Interpret as "Admin Approval"
     NONE = 1;
     ADMIN_APPROVAL = 2;
   }
@@ -308,7 +313,7 @@ message CallLink {
 
 message AdHocCall {
   enum State {
-    UNKNOWN_STATE = 0;
+    UNKNOWN_STATE = 0; // Interpret as "Generic"
     GENERIC = 1;
   }
 
@@ -324,6 +329,7 @@ message DistributionListItem {
   // by an all-0 UUID (00000000-0000-0000-0000-000000000000).
   bytes distributionId = 1; // distribution list ids are uuids
 
+  // If unset, importers should skip the item entirely without showing an error.
   oneof item {
     uint64 deletionTimestamp = 2;
     DistributionList distributionList = 3;
@@ -332,7 +338,7 @@ message DistributionListItem {
 
 message DistributionList {
   enum PrivacyMode {
-    UNKNOWN = 0;
+    UNKNOWN = 0; // Interpret as "Only with"
     ONLY_WITH = 1;
     ALL_EXCEPT = 2;
     ALL = 3;
@@ -367,12 +373,14 @@ message ChatItem {
   repeated ChatItem revisions = 6; // ordered from oldest to newest
   bool sms = 7;
 
+  // If unset, importers should skip this item without throwing an error.
   oneof directionalDetails {
     IncomingMessageDetails incoming = 8;
     OutgoingMessageDetails outgoing = 9;
     DirectionlessMessageDetails directionless = 10;
   }
 
+  // If unset, importers should skip this item without throwing an error.
   oneof item {
     StandardMessage standardMessage = 11;
     ContactMessage contactMessage = 12;
@@ -421,6 +429,7 @@ message SendStatus {
   uint64 recipientId = 1;
   uint64 timestamp = 2; // the time the status was last updated -- if from a receipt, it should be the sentTime of the receipt
 
+  // If unset, importers should consider the status to be "pending"
   oneof deliveryStatus {
     Pending pending = 3;
     Sent sent = 4;
@@ -457,6 +466,7 @@ message DirectStoryReplyMessage {
     FilePointer longText = 2;
   }
 
+  // If unset, importers should ignore the message without throwing an error.
   oneof reply {
     TextReply textReply = 1;
     string emoji = 2;
@@ -475,7 +485,7 @@ message PaymentNotification {
 
     message FailedTransaction { // Failed payments can't be synced from the ledger
       enum FailureReason {
-        GENERIC = 0;
+        GENERIC = 0; // A valid value -- reason unknown
         NETWORK = 1;
         INSUFFICIENT_FUNDS = 2;
       }
@@ -484,7 +494,7 @@ message PaymentNotification {
 
     message Transaction {
       enum Status {
-        INITIAL = 0;
+        INITIAL = 0; // A valid value -- state unconfirmed
         SUBMITTED = 1;
         SUCCESSFUL = 2;
       }
@@ -501,6 +511,7 @@ message PaymentNotification {
       optional bytes receipt = 7; // mobile coin blobs
     }
 
+    // If unset, importers should treat the transaction as successful with no metadata.
     oneof payment {
       Transaction transaction = 1;
       FailedTransaction failedTransaction = 2;
@@ -515,7 +526,7 @@ message PaymentNotification {
 
 message GiftBadge {
   enum State {
-    UNOPENED = 0;
+    UNOPENED = 0; // A valid state
     OPENED = 1;
     REDEEMED = 2;
     FAILED = 3;
@@ -543,7 +554,7 @@ message ContactAttachment {
 
   message Phone {
     enum Type {
-      UNKNOWN = 0;
+      UNKNOWN = 0; // Interpret as "Home"
       HOME = 1;
       MOBILE = 2;
       WORK = 3;
@@ -557,7 +568,7 @@ message ContactAttachment {
 
   message Email {
     enum Type {
-      UNKNOWN = 0;
+      UNKNOWN = 0; // Intepret as "Home"
       HOME = 1;
       MOBILE = 2;
       WORK = 3;
@@ -571,7 +582,7 @@ message ContactAttachment {
 
   message PostalAddress {
     enum Type {
-      UNKNOWN = 0;
+      UNKNOWN = 0; // Interpret as "Home"
       HOME = 1;
       WORK = 2;
       CUSTOM = 3;
@@ -631,7 +642,7 @@ message MessageAttachment {
   // but explicitly mutually exclusive. Note the different raw values
   // (non-zero starting values are not supported in proto3.)
   enum Flag {
-    NONE = 0;
+    NONE = 0; // A valid value -- no flag applied
     VOICE_MESSAGE = 1;
     BORDERLESS = 2;
     GIF = 3;
@@ -682,6 +693,7 @@ message FilePointer {
   message InvalidAttachmentLocator {
   }
 
+  // If unset, importers should consider it to be an InvalidAttachmentLocator without throwing an error.
   oneof locator {
     BackupLocator backupLocator = 1;
     AttachmentLocator attachmentLocator = 2;
@@ -700,7 +712,7 @@ message FilePointer {
 
 message Quote {
   enum Type {
-    UNKNOWN = 0;
+    UNKNOWN = 0; // Interpret as "Normal"
     NORMAL = 1;
     GIFT_BADGE = 2;
     VIEW_ONCE = 3;
@@ -721,7 +733,7 @@ message Quote {
 
 message BodyRange {
   enum Style {
-    NONE = 0;
+    NONE = 0; // Importers should ignore the body range without throwing an error.
     BOLD = 1;
     ITALIC = 2;
     SPOILER = 3;
@@ -734,6 +746,7 @@ message BodyRange {
   uint32 start = 1;
   uint32 length = 2;
 
+  // If unset, importers should ignore the body range without throwing an error.
   oneof associatedValue {
     bytes mentionAci = 3;
     Style style = 4;
@@ -750,6 +763,7 @@ message Reaction {
 }
 
 message ChatUpdateMessage {
+  // If unset, importers should ignore the update message without throwing an error.
   oneof update {
     SimpleChatUpdate simpleUpdate = 1;
     GroupChangeChatUpdate groupChange = 2;
@@ -765,19 +779,19 @@ message ChatUpdateMessage {
 
 message IndividualCall {
   enum Type {
-    UNKNOWN_TYPE = 0;
+    UNKNOWN_TYPE = 0; // Interpret as "Audio call"
     AUDIO_CALL = 1;
     VIDEO_CALL = 2;
   }
 
   enum Direction {
-    UNKNOWN_DIRECTION = 0;
+    UNKNOWN_DIRECTION = 0; // Interpret as "Incoming"
     INCOMING = 1;
     OUTGOING = 2;
   }
 
   enum State {
-    UNKNOWN_STATE = 0;
+    UNKNOWN_STATE = 0; // Interpret as "Accepted"
     ACCEPTED = 1;
     NOT_ACCEPTED = 2;
     // An incoming call that is no longer ongoing, which we neither accepted
@@ -798,7 +812,7 @@ message IndividualCall {
 
 message GroupCall {
   enum State {
-    UNKNOWN_STATE = 0;
+    UNKNOWN_STATE = 0; // Interpret as "Generic"
     // A group call was started without ringing.
     GENERIC = 1;
     // We joined a group call that was started without ringing.
@@ -829,7 +843,7 @@ message GroupCall {
 
 message SimpleChatUpdate {
   enum Type {
-    UNKNOWN = 0;
+    UNKNOWN = 0; // Importers should skip the update without throwing an error.
     JOINED_SIGNAL = 1;
     IDENTITY_UPDATE = 2;
     IDENTITY_VERIFIED = 3;
@@ -863,6 +877,7 @@ message ProfileChangeChatUpdate {
 }
 
 message LearnedProfileChatUpdate {
+  // If unset, importers should consider the previous name to be an empty string.
   oneof previousName {
     uint64 e164 = 1;
     string username = 2;
@@ -879,6 +894,7 @@ message SessionSwitchoverChatUpdate {
 
 message GroupChangeChatUpdate {
   message Update {
+    // If unset, importers should consider it to be a GenericGroupUpdate with unset updaterAci
     oneof update {
       GenericGroupUpdate genericGroupUpdate = 1;
       GroupCreationUpdate groupCreationUpdate = 2;
@@ -948,7 +964,7 @@ message GroupDescriptionUpdate {
 }
 
 enum GroupV2AccessLevel {
-  UNKNOWN = 0;
+  UNKNOWN = 0; // Interpret as "Unsatisfiable"
   ANY = 1;
   MEMBER = 2;
   ADMINISTRATOR = 3;
@@ -1138,6 +1154,7 @@ message ChatStyle {
   message CustomChatColor {
     uint64 id = 1;
 
+    // If unset, use the default chat color
     oneof color {
       fixed32 solid = 2; // 0xAARRGGBB
       Gradient gradient = 3;
@@ -1148,7 +1165,7 @@ message ChatStyle {
   }
 
   enum WallpaperPreset {
-    UNKNOWN_WALLPAPER_PRESET = 0;
+    UNKNOWN_WALLPAPER_PRESET = 0; // Interpret as the wallpaper being unset
     SOLID_BLUSH = 1;
     SOLID_COPPER = 2;
     SOLID_DUST = 3;
@@ -1173,7 +1190,7 @@ message ChatStyle {
   }
 
   enum BubbleColorPreset {
-    UNKNOWN_BUBBLE_COLOR_PRESET = 0;
+    UNKNOWN_BUBBLE_COLOR_PRESET = 0; // Interpret as the user's default chat bubble color
     SOLID_ULTRAMARINE = 1;
     SOLID_CRIMSON = 2;
     SOLID_VERMILION = 3;
@@ -1198,6 +1215,7 @@ message ChatStyle {
     GRADIENT_TANGERINE = 22;
   }
 
+  // If unset, importers should consider there to be no wallpaper.
   oneof wallpaper {
     WallpaperPreset wallpaperPreset = 1;
     // This `FilePointer` is expected not to contain a `fileName`, `width`,
@@ -1205,6 +1223,7 @@ message ChatStyle {
     FilePointer wallpaperPhoto = 2;
   }
 
+  // If unset, importers should consider it to be AutomaticBubbleColor
   oneof bubbleColor {
     // Bubble setting is automatically determined based on the wallpaper setting,
     // or `SOLID_ULTRAMARINE` for `noWallpaper`
@@ -1220,7 +1239,7 @@ message ChatStyle {
 
 message NotificationProfile {
   enum DayOfWeek {
-    UNKNOWN = 0;
+    UNKNOWN = 0; // Interpret as "Monday"
     MONDAY = 1;
     TUESDAY = 2;
     WEDNESDAY = 3;
@@ -1246,7 +1265,7 @@ message NotificationProfile {
 message ChatFolder {
   // Represents the default "All chats" folder record vs all other custom folders
   enum FolderType {
-    UNKNOWN = 0;
+    UNKNOWN = 0; // Interpret as "Custom"
     ALL = 1;
     CUSTOM = 2;
   }
diff --git a/ts/services/backups/import.ts b/ts/services/backups/import.ts
index 956e089f9..7ea79116e 100644
--- a/ts/services/backups/import.ts
+++ b/ts/services/backups/import.ts
@@ -480,8 +480,8 @@ export class BackupImportStream extends Writable {
           // Not a conversation
           return;
         } else {
-          log.warn(`${this.#logId}: unsupported recipient item`);
-          return;
+          log.warn(`${this.#logId}: unsupported recipient destination`);
+          throw new Error('Unsupported recipient destination');
         }
 
         if (convo !== this.#ourConversation) {
@@ -505,6 +505,7 @@ export class BackupImportStream extends Writable {
         await this.#fromAdHocCall(frame.adHocCall);
       } else {
         log.warn(`${this.#logId}: unsupported frame item ${frame.item}`);
+        throw new Error('Unsupported frame type');
       }
     } catch (error) {
       this.#frameErrorCount += 1;
@@ -940,11 +941,12 @@ export class BackupImportStream extends Writable {
       );
       attrs.discoveredUnregisteredAt = timestamp || this.#now;
       attrs.firstUnregisteredAt = timestamp || undefined;
-    } else {
-      strictAssert(
+    } else if (!contact.registered) {
+      log.error(
         contact.registered,
-        'contact is either registered or unregistered'
+        'contact is neither registered nor unregistered; treating as registered'
       );
+      this.#frameErrorCount += 1;
     }
 
     if (contact.blocked) {
@@ -1649,7 +1651,12 @@ export class BackupImportStream extends Writable {
         } else if (status.skipped) {
           sendStatus = SendStatus.Skipped;
         } else {
-          throw new Error(`Unknown sendStatus received: ${status}`);
+          log.error(
+            `${timestamp}: Unknown sendStatus received: ${status}, falling back to Pending`
+          );
+          // We fallback to pending for unknown send statuses
+          sendStatus = SendStatus.Pending;
+          this.#frameErrorCount += 1;
         }
 
         sendStateByConversationId[target.id] = {
@@ -1896,6 +1903,10 @@ export class BackupImportStream extends Writable {
         targetAuthorAci: storyAuthorAci,
         targetTimestamp: 0, // stories are never imported
       };
+    } else {
+      throw new Error(
+        'Direct story reply message missing both textReply and emoji'
+      );
     }
 
     return result;
@@ -2413,10 +2424,12 @@ export class BackupImportStream extends Writable {
 
     if (updateMessage.learnedProfileChange) {
       const { e164, username } = updateMessage.learnedProfileChange;
-      strictAssert(
-        e164 != null || username != null,
-        'learnedProfileChange must have an old name'
-      );
+      if (e164 == null && username == null) {
+        log.error(
+          `${options.timestamp}: learnedProfileChange had no previous e164 or username`
+        );
+        this.#frameErrorCount += 1;
+      }
       return {
         message: {
           type: 'title-transition-notification',
@@ -3392,7 +3405,7 @@ export class BackupImportStream extends Writable {
         value = {
           start: rgbIntToDesktopHSL(color.solid),
         };
-      } else {
+      } else if (color.gradient) {
         strictAssert(color.gradient != null, 'Either solid or gradient');
         strictAssert(color.gradient.colors != null, 'Missing gradient colors');
 
@@ -3409,6 +3422,12 @@ export class BackupImportStream extends Writable {
           end: rgbIntToDesktopHSL(end),
           deg,
         };
+      } else {
+        log.error(
+          'CustomChatColor missing both solid and gradient fields, dropping'
+        );
+        this.#frameErrorCount += 1;
+        continue;
       }
 
       customColors.colors[uuid] = value;
@@ -3532,16 +3551,23 @@ export class BackupImportStream extends Writable {
           color = 'ultramarine';
           break;
       }
-    } else {
-      strictAssert(chatStyle.customColorId != null, 'Missing custom color id');
-
+    } else if (chatStyle.customColorId != null) {
       const entry = this.#customColorById.get(
         chatStyle.customColorId.toNumber()
       );
-      strictAssert(entry != null, 'Missing custom color');
 
-      color = 'custom';
-      customColorData = entry;
+      if (entry) {
+        color = 'custom';
+        customColorData = entry;
+      } else {
+        log.error('Chat style referenced missing custom color');
+        this.#frameErrorCount += 1;
+        autoBubbleColor = true;
+      }
+    } else {
+      log.error('ChatStyle has no recognized field');
+      this.#frameErrorCount += 1;
+      autoBubbleColor = true;
     }
 
     return {
diff --git a/ts/services/backups/util/filePointers.ts b/ts/services/backups/util/filePointers.ts
index 638972264..8375ab9b5 100644
--- a/ts/services/backups/util/filePointers.ts
+++ b/ts/services/backups/util/filePointers.ts
@@ -120,15 +120,15 @@ export function convertFilePointerToAttachment(
     };
   }
 
-  if (invalidAttachmentLocator) {
-    return {
-      ...omit(commonProps, 'downloadPath'),
-      error: true,
-      size: 0,
-    };
+  if (!invalidAttachmentLocator) {
+    log.error('convertFilePointerToAttachment: filePointer had no locator');
   }
 
-  throw new Error('convertFilePointerToAttachment: mising locator');
+  return {
+    ...omit(commonProps, 'downloadPath'),
+    error: true,
+    size: 0,
+  };
 }
 
 export function convertBackupMessageAttachmentToAttachment(