diff --git a/cmdline/locate.c b/cmdline/locate.c
index 29aece03..8db53f11 100644
--- a/cmdline/locate.c
+++ b/cmdline/locate.c
@@ -33,6 +33,13 @@ struct snapraid_parity_entry {
 	tommy_node node;
 };
 
+struct snapraid_locate_info{
+    data_off_t block_max;
+	data_off_t parity_size;
+	block_off_t tail_block;
+    block_off_t min_occupied_block_number;
+};
+
 static int parity_entry_compare(const void* void_a, const void* void_b)
 {
 	const struct snapraid_parity_entry* entry_a = void_a;
@@ -112,6 +119,16 @@ static void collect_parity_block_file(uint32_t block_size, struct snapraid_disk*
 	tommy_list_insert_tail(file_list, &entry->node, entry);
 }
 
+void state_locate_info(struct snapraid_state* state, uint64_t parity_tail, struct snapraid_locate_info* info)
+{
+	uint64_t block_size = state->block_size;
+
+	info->block_max = parity_allocated_size(state);
+	info->parity_size = info->block_max * block_size;
+	info->tail_block = (parity_tail + block_size - 1) / block_size;
+	info->min_occupied_block_number = info->block_max - info->tail_block;
+}
+
 void state_locate(struct snapraid_state* state, uint64_t parity_tail)
 {
 	char buf[64];
@@ -127,20 +144,16 @@ void state_locate(struct snapraid_state* state, uint64_t parity_tail)
 		min_occupied_block_number = 0;
 	} else {
 		printf("Locate files within the tail of %sB of the parity\n\n", fmt_size(parity_tail, buf, sizeof(buf)));
-
-		data_off_t block_max = parity_allocated_size(state);
-		data_off_t parity_size = block_max * block_size;
-
-		printf("Current parity size is %sB\n", fmt_size(parity_size, buf, sizeof(buf)));
-
-		block_off_t tail_block = (parity_tail + block_size - 1) / block_size;
-
-		if (tail_block >= block_max) {
+		struct snapraid_locate_info info;
+		state_locate_info(state, parity_tail, &info);
+		
+		printf("Current parity size is %sB\n", fmt_size(info.parity_size, buf, sizeof(buf)));	
+		if (info.tail_block >= info.block_max) {
 			printf("Specified tail greater than the parity size!\n");
 			return;
 		}
 
-		min_occupied_block_number = block_max - tail_block;
+		min_occupied_block_number = info.min_occupied_block_number;
 	}
 
 	msg_progress("Collecting files with offset greater or equal to %" PRIu64 "\n", min_occupied_block_number * block_size);
@@ -179,3 +192,32 @@ void state_locate(struct snapraid_state* state, uint64_t parity_tail)
 	tommy_list_foreach(&files, free);
 }
 
+void state_locate_mark_tail_blocks_for_resync(struct snapraid_state* state, uint64_t parity_tail)
+{
+	struct snapraid_locate_info info;
+	state_locate_info(state, parity_tail, &info);
+	block_off_t min_occupied_block_number = info.min_occupied_block_number;				
+	printf("Forcing reallocation of all tail blocks from block number %u onwards\n", min_occupied_block_number);
+
+	for (tommy_node* i = tommy_list_head(&state->disklist); i != 0; i = i->next) {
+		struct snapraid_disk* disk = i->data;
+		for (tommy_node* j = tommy_list_head(&disk->filelist); j != 0; j = j->next) {
+			struct snapraid_file* file = j->data;
+			for (block_off_t f = 0; f < file->blockmax; ++f) {
+				block_off_t parity_pos = fs_file2par_find(disk, file, f);
+				if (parity_pos == POS_NULL)
+					continue; /* not allocated */
+				if (parity_pos < min_occupied_block_number)
+					continue; /* not relevant */
+
+				/* mark the file for reallocation */
+				struct snapraid_block* block = fs_file2block_get(file, f);
+				
+				// TODO: check: is condition correct or should we always set BLOCK_STATE_REP?
+				if (block_state_get(block) == BLOCK_STATE_BLK) {
+					block_state_set(block, BLOCK_STATE_REP);
+				}
+			}
+		}
+	}
+}
\ No newline at end of file
diff --git a/cmdline/locate.h b/cmdline/locate.h
index b9c99ddf..98294ce1 100644
--- a/cmdline/locate.h
+++ b/cmdline/locate.h
@@ -25,5 +25,6 @@
 
 void state_locate(struct snapraid_state* state, uint64_t parity_tail);
 
-#endif
+void state_locate_mark_tail_blocks_for_resync(struct snapraid_state* state, uint64_t parity_tail);
 
+#endif
diff --git a/cmdline/snapraid.c b/cmdline/snapraid.c
index 18400940..e278f3d8 100644
--- a/cmdline/snapraid.c
+++ b/cmdline/snapraid.c
@@ -58,26 +58,27 @@ void usage(const char* conf)
 	printf("  fix    Fix the array\n");
 	printf("\n");
 	printf("Options:\n");
-	printf("  " SWITCH_GETOPT_LONG("-c, --conf FILE       ", "-c") "  Configuration file\n");
-	printf("  " SWITCH_GETOPT_LONG("-f, --filter PATTERN  ", "-f") "  Process only files matching the pattern\n");
-	printf("  " SWITCH_GETOPT_LONG("-d, --filter-disk NAME", "-d") "  Process only files in the specified disk\n");
-	printf("  " SWITCH_GETOPT_LONG("-m, --filter-missing  ", "-m") "  Process only missing/deleted files\n");
-	printf("  " SWITCH_GETOPT_LONG("-e, --filter-error    ", "-e") "  Process only files with errors\n");
-	printf("  " SWITCH_GETOPT_LONG("-p, --plan PLAN       ", "-p") "  Define a scrub plan or percentage\n");
-	printf("  " SWITCH_GETOPT_LONG("-o, --older-than DAYS ", "-o") "  Process only the older part of the array\n");
-	printf("  " SWITCH_GETOPT_LONG("-i, --import DIR      ", "-i") "  Import deleted files\n");
-	printf("  " SWITCH_GETOPT_LONG("-l, --log FILE        ", "-l") "  Log file. Default none\n");
-	printf("  " SWITCH_GETOPT_LONG("-a, --audit-only      ", "-a") "  Check only file data and not parity\n");
-	printf("  " SWITCH_GETOPT_LONG("-h, --pre-hash        ", "-h") "  Pre-hash all the new data\n");
-	printf("  " SWITCH_GETOPT_LONG("-Z, --force-zero      ", "-Z") "  Force syncing of files that get zero size\n");
-	printf("  " SWITCH_GETOPT_LONG("-E, --force-empty     ", "-E") "  Force syncing of disks that get empty\n");
-	printf("  " SWITCH_GETOPT_LONG("-U, --force-uuid      ", "-U") "  Force commands on disks with uuid changed\n");
-	printf("  " SWITCH_GETOPT_LONG("-D, --force-device    ", "-D") "  Force commands with inaccessible/shared disks\n");
-	printf("  " SWITCH_GETOPT_LONG("-N, --force-nocopy    ", "-N") "  Force commands disabling the copy detection\n");
-	printf("  " SWITCH_GETOPT_LONG("-F, --force-full      ", "-F") "  Force a full parity computation in sync\n");
-	printf("  " SWITCH_GETOPT_LONG("-R, --force-realloc   ", "-R") "  Force a full parity reallocation in sync\n");
-	printf("  " SWITCH_GETOPT_LONG("-w, --bw-limit RATE   ", "-w") "  Limit IO bandwidth (M|G)\n");
-	printf("  " SWITCH_GETOPT_LONG("-v, --verbose         ", "-v") "  Verbose\n");
+	printf("  " SWITCH_GETOPT_LONG("-c, --conf FILE       	 ", "-c") "  Configuration file\n");
+	printf("  " SWITCH_GETOPT_LONG("-f, --filter PATTERN  	 ", "-f") "  Process only files matching the pattern\n");
+	printf("  " SWITCH_GETOPT_LONG("-d, --filter-disk NAME	 ", "-d") "  Process only files in the specified disk\n");
+	printf("  " SWITCH_GETOPT_LONG("-m, --filter-missing  	 ", "-m") "  Process only missing/deleted files\n");
+	printf("  " SWITCH_GETOPT_LONG("-e, --filter-error    	 ", "-e") "  Process only files with errors\n");
+	printf("  " SWITCH_GETOPT_LONG("-p, --plan PLAN       	 ", "-p") "  Define a scrub plan or percentage\n");
+	printf("  " SWITCH_GETOPT_LONG("-o, --older-than DAYS 	 ", "-o") "  Process only the older part of the array\n");
+	printf("  " SWITCH_GETOPT_LONG("-i, --import DIR      	 ", "-i") "  Import deleted files\n");
+	printf("  " SWITCH_GETOPT_LONG("-l, --log FILE        	 ", "-l") "  Log file. Default none\n");
+	printf("  " SWITCH_GETOPT_LONG("-a, --audit-only      	 ", "-a") "  Check only file data and not parity\n");
+	printf("  " SWITCH_GETOPT_LONG("-h, --pre-hash        	 ", "-h") "  Pre-hash all the new data\n");
+	printf("  " SWITCH_GETOPT_LONG("-Z, --force-zero      	 ", "-Z") "  Force syncing of files that get zero size\n");
+	printf("  " SWITCH_GETOPT_LONG("-E, --force-empty     	 ", "-E") "  Force syncing of disks that get empty\n");
+	printf("  " SWITCH_GETOPT_LONG("-U, --force-uuid      	 ", "-U") "  Force commands on disks with uuid changed\n");
+	printf("  " SWITCH_GETOPT_LONG("-D, --force-device    	 ", "-D") "  Force commands with inaccessible/shared disks\n");
+	printf("  " SWITCH_GETOPT_LONG("-N, --force-nocopy    	 ", "-N") "  Force commands disabling the copy detection\n");
+	printf("  " SWITCH_GETOPT_LONG("-F, --force-full      	 ", "-F") "  Force a full parity computation in sync\n");
+	printf("  " SWITCH_GETOPT_LONG("-R, --force-realloc   	 ", "-R") "  Force a full parity reallocation in sync\n");
+	printf("  " SWITCH_GETOPT_LONG("-X, --force-realloc-tail ", "-X") "  Force a tail parity reallocation in sync\n");
+	printf("  " SWITCH_GETOPT_LONG("-w, --bw-limit RATE   	 ", "-w") "  Limit IO bandwidth (M|G)\n");
+	printf("  " SWITCH_GETOPT_LONG("-v, --verbose         	 ", "-v") "  Verbose\n");
 	printf("\n");
 	printf("Configuration file: %s\n", conf);
 	printf("\n");
@@ -712,6 +713,7 @@ static struct option long_options[] = {
 	{ "force-nocopy", 0, 0, 'N' },
 	{ "force-full", 0, 0, 'F' },
 	{ "force-realloc", 0, 0, 'R' },
+	{ "force-realloc-tail", 0, 0, 'X' },
 	{ "bw-limit", 1, 0, 'w' },
 	{ "audit-only", 0, 0, 'a' },
 	{ "pre-hash", 0, 0, 'h' },
@@ -870,12 +872,12 @@ static struct option long_options[] = {
 #endif
 
 /*
- * Free letters: gIjJkKMnPQruxXWz
+ * Free letters: gIjJkKMnPQruxWz
  *
  * The 's' letter is used in main.c
  * The 'G' letter is free but only from 14.0
  */
-#define OPTIONS "t:c:f:d:mebp:o:S:B:L:i:l:AZEUDNFRahTC:vqHVw:"
+#define OPTIONS "X:t:c:f:d:mebp:o:S:B:L:i:l:AZEUDNFRahTC:vqHVw:"
 
 int parse_option_size(const char* arg, uint64_t* out_size)
 {
@@ -1197,6 +1199,9 @@ int snapraid_main(int argc, char* argv[])
 		case 'R' :
 			opt.force_realloc = 1;
 			break;
+		case 'X' :
+			opt.force_realloc_tail = 1;
+			break;
 		case 'a' :
 			opt.auditonly = 1;
 			break;
@@ -1548,6 +1553,13 @@ int snapraid_main(int argc, char* argv[])
 			exit(EXIT_FAILURE);
 			/* LCOV_EXCL_STOP */
 		}
+
+		if (opt.force_realloc_tail) {
+			/* LCOV_EXCL_START */
+			log_fatal(EUSER, "You cannot use -X, --force_realloc_tail with the '%s' command\n", command);
+			exit(EXIT_FAILURE);
+			/* LCOV_EXCL_STOP */
+		}
 	}
 
 	if (opt.force_full && opt.force_nocopy) {
@@ -1571,6 +1583,34 @@ int snapraid_main(int argc, char* argv[])
 		/* LCOV_EXCL_STOP */
 	}
 
+	if (opt.force_realloc && opt.force_realloc_tail) {
+		/* LCOV_EXCL_START */
+		log_fatal(EUSER, "You cannot use the -R, --force-realloc and -X, --force-realloc-tail options simultaneously\n");
+		exit(EXIT_FAILURE);
+		/* LCOV_EXCL_STOP */
+	}
+
+	if (opt.force_realloc_tail && opt.force_nocopy) {
+		/* LCOV_EXCL_START */
+		log_fatal(EUSER, "You cannot use the -X, --force-realloc-tail and -N, --force-nocopy options simultaneously\n");
+		exit(EXIT_FAILURE);
+		/* LCOV_EXCL_STOP */
+	}
+
+	if (opt.force_realloc_tail && opt.force_full) {
+		/* LCOV_EXCL_START */
+		log_fatal(EUSER, "You cannot use the -X, --force-realloc-tail and -F, --force-full options simultaneously\n");
+		exit(EXIT_FAILURE);
+		/* LCOV_EXCL_STOP */
+	}
+
+	if (opt.force_realloc_tail && parity_tail == 0) {
+		/* LCOV_EXCL_START */
+		log_fatal(EUSER, "You cannot use the -X, --force-realloc-tail without option 't' == 0 \n");
+		exit(EXIT_FAILURE);
+		/* LCOV_EXCL_STOP */
+	}
+
 	if (opt.prehash && opt.force_nocopy) {
 		/* LCOV_EXCL_START */
 		log_fatal(EUSER, "You cannot use the -h, --pre-hash and -N, --force-nocopy options simultaneously\n");
@@ -1813,6 +1853,11 @@ int snapraid_main(int argc, char* argv[])
 
 		state_read(&state);
 
+		// TODO: check if this is the correct place for marking, before or after regular scan?
+		// "scan_file_keep()"" will be called inside the following "state_scan()" so we have to mark the file before
+		if(state.opt.force_realloc_tail)
+			state_locate_mark_tail_blocks_for_resync(&state, parity_tail);
+
 		state_scan(&state);
 
 		/* refresh the size info before the content write */
diff --git a/cmdline/state.h b/cmdline/state.h
index c0cc8c4d..4db4f059 100644
--- a/cmdline/state.h
+++ b/cmdline/state.h
@@ -81,6 +81,7 @@ struct snapraid_option {
 	int force_nocopy; /**< Force dangerous operations of syncing files without using copy detection. */
 	int force_full; /**< Force a full parity update. */
 	int force_realloc; /**< Force a full reallocation and parity update. */
+	int force_realloc_tail; /**< Force a partial reallocation and parity update for tail space. */
 	int expect_unrecoverable; /**< Expect presence of unrecoverable error in checking or fixing. */
 	int expect_recoverable; /**< Expect presence of recoverable error in checking. */
 	int skip_device; /**< Skip devices matching checks. */